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Effects of the Application of Neck Pressure by a Collar or Harness on Intraocular Pressure in Dogs
Abstract
The effect on intraocular pressure (IOP) from dogs pulling against a collar or a harness was evaluated in 51 eyes of 26 dogs. The force each dog generated while pulling against a collar or a harness was measured. Intraocular pressure measurements were obtained during application of corresponding pressures via collars or harnesses. Intraocular pressure increased significantly from baseline when pressure was applied via a collar but not via a harness. Based on the results of the study, dogs with weak or thin corneas, glaucoma, or conditions for which an increase in IOP could be harmful should wear a harness instead of a collar, especially during exercise or activity.
... Physical and behavioural health are intrinsic to pet dog welfare, and behaviour changes may be veterinary professionals' (VPs) first indication of underlying disease processes and broader welfare concerns. 1 Left untreated, undesirable behaviours can compromise health; for example, recall problems causing accidents, 2 stress contributing to dermatitis, 3 lead pulling causing injuries, 4 separation anxiety leading to escape-related injuries 5 and wounds from interdog aggression. 6 Undesirable behaviours damage pet-owner attachment and are the leading cause of relinquishment and euthanasia in pet dogs under 3 years old. ...
... 73 While a plastic model cannot replicate responses of neck tissue to pressure, or account for intraspecies variability, every collar tested created pressure exceeding that which causes tissue damage in humans. Pauli et al. 4 found dogs experienced significantly higher intraocular pressure (IOP) when force was applied to a collar than a harness and suggested these effects could be heightened when actively lead pulling, due to the Valsalva manoeuvre. Persistently elevated IOP increases the likelihood of visual field loss in humans, 4 suggesting dogs that pull on lead might be at similar risk. ...
... Pauli et al. 4 found dogs experienced significantly higher intraocular pressure (IOP) when force was applied to a collar than a harness and suggested these effects could be heightened when actively lead pulling, due to the Valsalva manoeuvre. Persistently elevated IOP increases the likelihood of visual field loss in humans, 4 suggesting dogs that pull on lead might be at similar risk. ...
Veterinary professionals (VPs) are often the first source of advice for clients struggling with their dog’s behaviour, and pulling on the lead is a common-place undesirable behaviour VPs will encounter regularly in practice. Excluding bites, being pulled over while walking on a lead is the leading cause of non-fatal dog-related injuries in the UK. This narrative review investigates lead pulling as a welfare concern in pet dogs, highlighting aspects of the literature of particular interest to VPs. Lead pulling could negatively affect walk quality, frequency and duration,causing weight gain, while decreased environmental enrichment could trigger other undesirable behaviours. Aversive equipment to prevent lead pulling can cause pain, distress and injury, but even equipment considered humane can have welfare consequences. Punitive training methods could cause dogs stress, fear and anxiety and trigger aggressive behaviour. While these lead pulling outcomes are welfare concerns in themselves, they could also weaken dog–owner attachment, a risk factor in pet dog relinquishment.Given lead pulling could affect the welfare of patients in a VPs care, clinical implications and opportunities for client education are outlined. Educating clients on humane prevention and modification of lead pulling could make walks easier, safer and more enjoyable, with positive outcomes for clients,canine welfare and the practice.
... Researchers have investigated the controlling effects and potential welfare concerns of different restraint types. For dogs wearing collars, excess pressure on the neck may cause musculoskeletal and tracheal injuries, and/or have negative effects on their eyes (11). Ogburn et al. (12) found that, compared to head collars, dogs were more disobedient on the leash while wearing traditional neck collars, although no significant differences in physiological responses, including blood pressure, pulse rate, respiratory rate, pupil diameter, and plasma cortisol concentrations, were detected. ...
... However, in the current study, dogs were tested in only a mildly to moderately excited state. Thus, we do not dismiss the concern with respect to the potential for tissue damage and health concerns resulting from the compression of the neck from a neck collar, especially when dogs are highly aroused (11,34). Under the harness condition, dogs spent more time looking at the experimenter when tested with food treats and this might relate to differences in how the restraints are perceived. ...
... Future studies should consider randomising the testing object or confirm the interest of the dog to the object before testing. Finally, future studies might build on this by examining the effects of breed on the results, since some dog breeds have been specifically bred to pull objects (e.g., Alaskan malamutes and Siberian huskies), and may be more resistant to the pressure resulting from leash pulling (11). ...
Leash pulling is a concern for dog owners and can be detrimental to the health and welfare of dogs. Neck-collars and back-connection harnesses are popular restraint types. Harnesses have been proposed as a better and more considerate option for canine health and welfare. Anecdotally, dogs pull more when wearing a back-connection harness; however, there is no scientific evidence for this perception. This study aimed to investigate how strongly dogs pull on the lead to achieve a food treat or toy under restraint by a neck-collar versus a back-connection harness. A within-subject counterbalanced design was used for the study, involving 52 shelter dogs. A customised canine leash tension metre was connected to the collar or harness to record the pulling of the dogs, including measuring the maximal and mean leash tension, and the time spent pulling. In addition, dog behaviours were recorded using two cameras from two separate directions. The maximal and mean leash tension and the pulling time were greater under restraint by harness when attracting dogs with food treats. No significant difference between harness and collar was found in potential stress-related behaviours (e.g. tail and ear positions, lip-licking, and panting). However, dogs looked at the experimenter more often when restrained by harness than collar in the food treat attraction test. No significant difference was detected between harness and collar with respect to leash tension and stress-related behaviours in the toy attraction test. These findings suggest that dogs tend to pull stronger and more steadily when wearing a back-connection harness compared to a neck collar to reach the food treat but not the toy.
... 2,[12][13][14] Age is another factor, and IOP is 2-4 mm Hg lower in dogs older than six years of age than in younger dogs. 15 Furthermore, artefacts such as pressure on the jugular veins from excessive restraint 16 and pressure on the eyelids and the orbital area [17][18][19][20] may also affect readings. ...
... The study population included 29 Labrador retrievers and two German shepherds, and comprised of 22 castrated males and nine spayed females. The dogs' mean ± SD (minimummaximum, median) age was 13.6 ± 3.1 (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)14) months. In 13 males and three females (52% of all dogs) the right eye was measured first. ...
... Theoretically, IOP differences between eyes may be due to iatrogenic artefacts, such as compression of the jugular vein 16 or digital pressure on the eyelids and globe during measurement of one eye or the other. 1,2,10, 17 We took special care to avoid such manipulations, and the same investigator collected all measurements with both tonometers. ...
Purpose:
To determine whether the order of intraocular pressure (IOP) measurement affects readings, regardless of which eye is measured first.
Methods:
Intraocular pressure was measured in 31 and 41 dogs using applanation and rebound tonometry, respectively. Initially, IOP was measured in the first (randomly chosen) eye (reading A), followed by measurement in the fellow eye (reading B), and a third (repeated) measurement in the first eye (reading C). After 15 minutes, measurements were repeated in reverse order (readings D - F).
Results:
Applanation tonometry revealed significant differences between readings A & B (15.6 ± 2.3 and 14.8 ± 2.7 mm Hg, respectively, p = .02), A & C (15.6 ± 2.3 and 14.5 ± 2.4 mm Hg, respectively, p = .002), D & E (14.5 ± 2.3 and 13.7 ± 2.1 mm Hg, respectively, p = .02), D & F (14.5 ± 2.3 and 13.9 ± 1.9 mm Hg, respectively, p = .05), and A & E (15.6 ± 2.3 and 13.7 ± 2.1 mm Hg, respectively, p = .001). Rebound tonometry yielded similar results, with additional differences between B & C (19.1 ± 3.0 and 18.2 ± 2.4 mm Hg, respectively, p = .002) and E & F (18.7 ± 3.3 and 18.2 ± 3.3 mm Hg, respectively, p = .02).
Conclusions:
Intraocular pressure measured in the first eye, whether right or left, is higher than in the fellow eye. Repeated tonometry in the same visit could result in a significant IOP decrease, though the magnitude may not be clinically appreciable.
... Intraocular pressure in different species may be affected by several factors such as age, restraint method, temperament of the patient, presence of corneal disease, and time of the day in which tonometry is performed. 11,12,[23][24][25][26][30][31][32][33][34][35][36][37][38][39][40][41][42][43] Previous IOP studies in guinea pigs found that the type of tonometry and time of the day were determinant factors for establishing a reference IOP values for this species. 7,8,11,12 The present study found a difference in IOP between young and adult guinea pigs, and based on these results we can now provide reference values for young animals. ...
... 43 Tonometry values may be significantly affected in dogs, horses, and humans by compression of both jugular veins, traction on the eyelids, tied collars, and body or head position. [30][31][32][33][34] The majority of IOP measurements in the present study were obtained with no restraint, which may have eliminated an increase in IOP due to neck compression. ...
Fifty-two guinea pigs (Cavia porcellus) with normal ophthalmic examination were included in this study to determine whether there are differences in the intraocular pressure (IOP) according to age, while assessing the clinical usefulness of two different tonometry methods for this species. The animals were divided into 2 groups according to age: young (4 weeks-old, 29 animals) and adult (3–36 months, 23 animals). Tonometry was performed oculus utro (OU) in the central cornea according to the manufacturer′s recommendations. Only measurements with low standard deviation (SD<5%) were included. Rebound tonometry was performed first OU; following topical anesthesia, applanation tonometry was then performed OU. The time required to obtain an IOP value was recorded for each eye. Descriptive statistics were calculated and Lin Concordance Coefficient (LCC) was performed to describe concordance between methods. Mean TonoVet® IOP readings were 8.53±1.28 mmHg and 13.20±1.28 mmHg for young and adults, respectively (p<0.05). Tono-Pen VET® readings could not be obtained in young animals, but yielded a mean of 10.93±3.61 mmHg in adults. No differences were found between left and right eyes (p>0.05) nor between genders (p>0.05). TonoVet® readings were obtained faster than Tono-Pen VET® readings (less than 1 min vs 3.38±1.27 min, respectively (p<0.05)). Lin Concordance Coefficient between methods was 0.37 (95% CI 0.19; 0.53⁾, documenting a poor concordance between the two methods. The study states that normal IOP values are lower in young than in adult guinea pigs. Moreover, the results obtained from this investigation demonstrated that TonoVet® tonometry is a rapid and well-tolerated procedure when performed on guinea pigs of any age, whereas Tono-Pen VET® tonometry is a more time-consuming technique that can only be used on guinea pigs older than 3 months.
... It is also possible that using certain punitive techniques presents more direct health risks. One study showed increased intraocular pressure in dogs while pulling against a collar (Pauli et al., 2006). Importantly, 1 extreme case report of the effects of a specific punitive technique on the physical health of a 1-year-old German Shepherd dog was found (Grohmann et al., 2013). ...
... Because the use of such aversive methods may still be prevalent, it is unlikely that this is the only case. In addition, many punitive techniques involve pressure on the neck, which may lead to dangerous increases in intraocular pressure (see Pauli et al., 2006). Veterinarians should be encouraged to publish case studies in which dogs were injured due to the use of aversive training methods. ...
The purpose of this paper is to review a series of studies (N= 17) regarding the effects of using various methods when training dogs. The reviewed studies examined the differences between training methods (e.g., methods based on positive reinforcement, positive punishment, escape/avoidance, etc.) on a dog’s physiology, welfare, and behavior towards humans and other dogs. The reviewed studies included surveys, observational studies, and interventions. The results show that using aversive training methods (e.g., positive punishment and negative reinforcement) can jeopardize both the physical and mental health of dogs. In addition, while positive punishment can be effective, there is no evidence that it is more effective than positive reinforcement-based training. In fact, there is some evidence that the opposite is true. A few methodological concerns arose from the reviewed studies. Among them are small sample sizes, missing data on effect size, possible bias when coding behavior in observational studies, and the need to publish case reports of bodily damage caused by aversive training methods. In conclusion, those working with or handling dogs should rely on positive reinforcement methods, and avoid using positive punishment and negative reinforcement as much as possible.
... Although a leash attached to a neck collar is the most common form of restraint in most countries, concern has been raised over the potential for them to cause damage to the neck and trachea (Landsberg et al., 2013). Neck collars can also have a negative effect on the welfare of individuals with eye conditions, such as glaucoma or weak corneas (Pauli et al., 2006). Head collars or harnesses may also be more suitable for specific breeds of dog, such as those possessing slim delicate necks, which may potentially be damaged by collars. ...
... Neck collars are widely used as a form of canine restraint, but concerns have been raised about their use (e.g., Pauli et al., 2006;Landsberg et al., 2013). Harnesses are an alternative form of restraint, which have been anecdotally proposed to be better for canine welfare. ...
Dogs are a popular pet in the United Kingdom and walking a dog is widely recognized as an important part of dog ownership. A number of different restraints can be used when walking dogs on leashes such as collars and harnesses. Previous research has examined the behavioral effects of walking dogs on head and neck collars. Harnesses are often anecdotally proposed to be more beneficial to dog welfare than other alternative restraints, however to date the effects of walking dogs on harnesses have not been investigated. The aim of this study was to determine the behavioral responses of dogs walked on neck collars or harnesses. The broader purpose of this study was to examine if the type of restraint worn causes stress in dogs. In order to explore this, a within-subject counterbalanced design was used. Thirty privately owned dogs were recruited within two groups (each group: n=15); those previously walked on a harness and those previously walked on a neck collar. Dogs were walked for 20 minutes each while behavioral indicators of stress were recorded. Post this trial, owners were given the alternative walking restraint and returned a week later to perform a second 20 minute walk. Behavioral indicators were again recorded. No significant differences were found between behaviors shown by dogs when walked on either collar or harness. However dogs with a history of being walked on a collar showed increased low ear position. This may suggest that these dogs are more stressed however due to the lack of support from the other stress indicators, motivations, such as indicating appeasement toward their owners, should also be considered. These findings suggest that, at least for the specific harness and collar trialed, neither neck collars nor harnesses are eliciting stress in dogs. However, future research determining the long-term effects of neck collar and harness use would be beneficial.
... The other needle was connected to a pressure transducer (NL108T2 Disposable Physiological Pressure Transducer, Warner Instruments, Hamden, CT) and continuous physiologic recorder (Dash â 4000 Pro, GE Healthcare, Milwaukee, WI) allowing IOP to be verified and continuously recorded. Triplicate TonoLab â followed by TonoVet â readings were acquired as described below, by the same observer (CD) at 5,10,15,20,25,30,35,40,50,60,70, and 80 mmHg for each eye. ...
... In other studies, IOP increases in a range of species were observed with jugular compression. [23][24][25] Thus, manual restraint method should be reported and carefully considered when interpreting IOP data in redeared slider turtles, and rostral head or no manual restraint are preferred, due to the lack of significant effect on IOP. In addition, head and body position was shown to impact IOP in a range of species, 11,23,26 but both were consistent across groups in our study as turtles were consistently supported with their head and body in a horizontal position during all restraint methods evaluated. ...
Objective
To evaluate feasibility and accuracy of intraocular pressure (IOP) measurement by rebound tonometry in adult red-eared slider turtles and determine the effects of manual and chemical restraint on IOP. Animal studiedSeventeen adult red-eared slider turtles. ProceduresIntraocular pressure was measured with TonoLab® and TonoVet® tonometers in conscious, unrestrained turtles. To evaluate the effects of manual restraint, turtles were restrained by digital pressure on the rostral head or proximal neck. The effect of two chemical restraint protocols (dexmedetomidine, ketamine, midazolam [DKM] and dexmedetomidine, ketamine [DK] subcutaneously) on IOP was evaluated. Triplicate TonoLab® and TonoVet® readings were compared with direct manometry in three ex vivo turtle eyes. ResultsTonoLab® correlated better with manometry at IOPs < 45 mmHg than TonoVet® (linear regression slopes of 0.89 and 0.30, respectively). Mean (±SD) IOP in unrestrained conscious turtles was significantly lower (P < 0.01) with TonoLab® (10.02 ± 0.66 mmHg) than with TonoVet® (11.32 ± 1.57 mmHg). Manual neck restraint caused a significant increase in IOP (+6.31 ± 5.59 mmHg), while manual rostral head restraint did not. Both chemical restraint protocols significantly reduced IOP (DKM: −1.0 ± 0.76 mmHg; DK: −1.79 ± 1.17) compared with measurements in conscious unrestrained turtles. Conclusions
Chemical and manual neck restraint affected IOP. Rostral head restraint had no significant effect on IOP and is, therefore, recommended as the appropriate restraint technique in red-eared slider turtles. TonoLab® measurements estimated actual IOP more accurately, within physiologic range, than measurements obtained using the TonoVet®.
... Reuter et al., (2011) reported that body position has a significant effect on Tawny owls and Common buzzards' IOP values. In addition, pressure applied to the eye or neck during measurement and changes in blood pressure due body positions can be counted among the factors that affect IOP values (Pauli et al., 2006). The risk factors were minimized for the correct measurement in this study. ...
In the present study, intraocular pressures (IOP) of 66 Buzzards (132 eyes), 20 Hawks (40 eyes), 13 Owls (26 eyes), 6 Eagles (12 eyes), 6 Kestrels (12 eyes), 4 Falcons (8 eyes), 2 Vultures (4 eyes), which referred to Erciyes University, Faculty of Veterinary Medicine, Department of Surgery Clinic were evaluated. In the ophthalmologic examination there was no lesion detected related to eyes. The mean body weight raptors was 1.10±0.23 kg (Buzzards), 0.23±0.06 kg (Hawks), 0.27±0.10 (Owls), 3.30±0.80 kg (Eagles), 0,18±0.04 kg (Kestrels), 0,64±0,28 kg (Falcons) and 2.28±0.43 kg (Vultures). Rebound tonometer (Tonovet) was used for measurement of IOP. Mean intraocular pressures of right and left eyes were in Buzzards 25.87±0.62-26.61±0.71, Hawks 11.90±0.40-12.05±0.41, Owls 12.00±0.63-12.61±0.57, Eagles 29.00±2.89-30.33±2.87, Kestrels 11.75±0.17-10.83±0.47, Falcons 14.75±1.10-14.25±0.85 and Vultures 15.00±1.00-14.50±0.50. As a result of the study, repeated intraocular pressure measurements of raptors can be made by using rebound tonometer. In addition, the application of rebound tonometer is very easy to application do not require local anaesthetic. Therefore, raptors may be able to tolerate the application easily. The present data are considered to contribute to the literature.
... Presumably, they are related to a complex balance of factors, such introduction The measurement of intraocular pressure (IOP) is a routine procedure commonly conducted during ophthalmic examinations (FEATHERSTONE and HEINRIcH, 2013). It has been documented in dogs that sedative drugs (HOFmEISTER et al., 2009;GHAFFARI et al., 2010), the head and body position (KlEIN et al., 2011;PAUlI et al., 2006), the circadian rhythm (GIANNETTO et al., 2009), the gender and season may influence IOP, PR and arterial blood pressure were measured before starting the treadmill exercise (at rest) (T0), immediately after the exercise (T1), and at the end of the recovery period (T2). The IOP was recorded by applanation tonometry (TonoVet ® , Tiolat ltd, Helsinki, Finland) after administration of a topical anesthetic (Oxybuprocaine Hydrochloride 0.4%, Novartis Farma, Italy) by the same operator (M.R.). ...
Physical exercise in humans induces changes in intraocular pressure, relating to the type and intensity of the workload. The purpose of the present study was to evaluate the variations in intraocular pressure and arterial blood pressure in dogs that underwent physical exercise on a treadmill. Thirty dogs were submitted to physical exercise consisting of walking (15 minutes), trotting (20 minutes), and walking (10 minutes). The intraocular pressure, blood pressure and pulse rate were recorded for each dog before starting the treadmill exercise, immediately after it ended, and after 20 minutes of passive recovery. Two-way repeated analysis of variance measurement showed the significant effect of treadmill exercise (P≤0.01) on intraocular pressure, pulse rate and diastolic blood pressure. No significant changes were observed to systolic blood pressure. Intraocular pressure and diastolic blood pressure decreased significantly during the passive recovery, and were strongly related. The pulse rate was significantly lower during the passive recovery. Although the mechanism determining the reduction in intraocular pressure during exercise remains not fully understood, our results suggest that it is strongly related to variations in arterial blood pressure.
... However, leash pulling is one of the most common issues reported in shelter dogs within 1 month postadoption (34). It can be detrimental to the health of the dog (35) and is related to handlers' musculoskeletal injuries (36). Also, it is equally important that how handlers hold the leash because owners jerking on the leash can cause severe health concerns to the dogs (37). ...
Different people relate to dogs in different ways. We investigated differences between volunteers in their behavioural interactions with shelter dogs when they were walked on a leash. Cameras were used to record and quantify the behaviour of volunteers and a leash tension metre was used to measure pulling by both volunteers and shelter dogs. Effects of volunteers' age, body height, educational level, marital status, and experiences of living and working with dogs, and living with children, were examined. Older volunteers talked to the dogs more often during the walk than younger ones. Taller volunteers had reduced physical contact with dogs, and dogs pulled more frequently on the leash while walking with them. Volunteers with a postgraduate degree more frequently praised dogs and rewarded dogs with food and used more body language in the form of hand gestures and physical contact. Married and partnered volunteers more often praised dogs, while separated/divorced or widowed volunteers initiated more frequent physical contacts. Dogs pulled less when walking with volunteers who had experience of living with dogs, and these volunteers interacted with dogs using fewer verbal and body languages. Finally, those living with children more frequently communicated with dogs using body language (e.g., hand gestures and physical contact). We conclude that shelters should carefully consider volunteers' demographics when selecting them to walk dogs with various behavioural characteristics.
... During the each IOP measurement, the rabbits were gently handled to prevent any pressure on the animal's neck which might effect IOP [18] . All measurements were recorded at predefined time points [9] . ...
This study was aimed to compare the effect of 1% atropine, 1% cyclopentolate, 0.5% tropicamide, and 10% phenylephrine eye drops on intraocular pressure (IOP) and central corneal thickness (CCT) in New Zealand White rabbits. Adult male, eight, New Zealand White rabbits were randomly received each of four mydriatic eye drops separately on left eye at a one-week washout period. Each rabbit received all of five different treatments (sterile saline solution, four mydriatic drugs) on the left eye, whereas no measurements were performed on the right eyes during the experiment. The IOP and CCT recordings of rabbits were performed until the pupil returned to normal diameter. The mean CCT values of sterile saline, 1% atropine, 0.5% tropicamide, 1% cyclopentolate, and 10% phenylephrine were 370±15, 368±17, 372±15, 364±18, and 360±17 µm, respectively, and no statistically significant differences (P>0.05) were observed among groups. The mean IOP values of control (sterile saline), 1% atropine, 0.5% tropicamide, 1% cyclopentolate, and 10% phenylephrine as, 9.7±2.1, 10.4±1.8, 10.3±2.1, 11.0±2.1, and 10±1.8 mmHg, respectively, and these were not statistically significant among groups (P>0.05). In conclusion, topical 1% atropine, 0.5% tropicamide 1% cyclopentolate, and 10% phenylephrine do not have significantly effect on IOP and CCT in New Zealand white rabbits.
... During the each IOP measurement, the rabbits were gently handled to prevent any pressure on the animal's neck which might effect IOP [18] . All measurements were recorded at predefined time points [9] . ...
This study was aimed to compare the eff ect of 1% atropine, 1% cyclopentolate, 0.5% tropicamide, and 10% phenylephrine eye drops on intraocular pressure (IOP) and central corneal thickness (CCT) in New Zealand White rabbits. Adult male, eight, New Zealand White rabbits were randomly received each of four mydriatic eye drops separately on left eye at a one-week washout period. Each rabbit received all of five diff erent treatments (sterile saline solution, four mydriatic drugs) on the left eye, whereas no measurements were performed on the right eyes during the experiment. The IOP and CCT recordings of rabbits were performed until the pupil returned to normal diameter. The mean CCT values of sterile saline, 1% atropine, 0.5% tropicamide, 1% cyclopentolate, and 10% phenylephrine were 370±15, 368±17, 372±15, 364±18, and 360±17 µm, respectively, and no statistically significant diff erences (P>0.05) were observed among groups. The mean IOP values of control (sterile saline), 1% atropine, 0.5 % tropicamide, 1% cyclopentolate, and 10% phenylephrine as, 9.7±2.1, 10.4±1.8, 10.3±2.1, 11.0±2.1, and 10±1.8 mmHg, respectively, and these were not statistically significant among groups (P>0.05). In conclusion, topical 1% atropine, 0.5% tropicamide 1% cyclopentolate, and 10% phenylephrine do not have significantly eff ect on IOP and CCT in New Zealand white rabbits. Öz Bu çalışma, Beyaz Yeni Zelanda tavşanlarında %1 atropin, %1 siklopentolat, %0.5 tropikamid ve %10 fenilefrin göz damlasının göz içi basıncı (GİB) ve merkezi kornea kalınlığı (MKK) üzerindeki etkilerini karşılaştırmayı amaçladı. Sekiz, yetişkin erkek Beyaz Yeni Zelanda tavşanının sol gözüne dört ayrı midriyatik göz damlası bir haftalık arınma periyoduyla rastgele uygulandı. Her tavşanın sol gözüne beş farklı tedavinin (steril serum fizyolojik, dört midriyatik ilaç) tamamı uygulanırken, sağ gözlerde ise deney boyunca ölçüm yapılmadı. Tavşanların GİB ve MKK verileri pupil normal çapa dönene kadar alındı. Steril salin, %1 atropin, %0.5 tropikamid, %1 siklopentolat ve %10 fenilefrinin ortalama MKK değerleri sırasıyla 370±15, 368±17, 372±15, 364±18 ve 360±17 µm idi ve gruplar arasında istatistiksel olarak anlamlı farklılık (P>0.05) gözlenmedi. Kontrol (steril salin), %1 atropin, %0.5 tropikamid, %1 siklopentolat ve %10 fenilefrinin ortalama GİB değerleri sırasıyla 9. mmHg'idi ve gruplar arasında istatistiksel olarak önem yoktu (P>0.05). Sonuç olarak, Beyaz Yeni Zelanda tavşanlarında topikal %1 atropin, %0.5 tropikamid, %1 siklopentolat ve %10 fenilefrinin GİB ve MKK üzerinde anlamlı bir etkisi yoktur.
... During the each IOP measurement, the rabbits were gently handled to prevent any pressure on the animal's neck which might effect IOP [18] . All measurements were recorded at predefined time points [9] . ...
... The use of a harness has been anecdotally proposed to improve canine welfare in comparison to the use of a collar and lead, which is considered to exert increased and potentially damaging pressure on the dog's neck and throat if the dog pulls ( Pauli et al., 2006 ; Landsberg et al., 1995 ;Grainger et al., 2016 ). However, few studies to date have investigated the physical effects of collar or harness use in pet or assistance dogs. ...
Studies have investigated the kinematics of the healthy canine thoracic limb (TL), but there is currently no research to the authors’ knowledge investigating the influence of the working harness on TL kinematics. The aim of this study was to compare the TL stride length (SL) and shoulder, elbow and carpal joint range of movement (ROM) of assistance dogs when wearing three different harnesses (H1 and H2 Y-shaped harnesses; H3 the dog's original harness) with differing handle designs (A and B type handles; all dogs used an A type handle with H3, their original harness), in comparison to a standard collar at walk. Thirteen dogs were analysed at walk in each condition: Harness 1, H1 (B-handle); Harness 2, H2 (A-handle); Harness 3, H3 (A-handle, and the dog's original working harness); and the Collar with the lead held between 20-40cm. A series of Friedman's analyses with post-hoc Wilcoxon Signed Rank tests compared SL and joint ROM at peak protraction and retraction of the TL. Results: The results show significant TL kinematic changes in H1 (B-handle): SL in H1 was significantly reduced in comparison to the Collar (6%; P=0.008). In TL protraction, a significant reduction in shoulder extension was recorded for H1 in comparison to H3 (6%; P=0.005). In TL retraction, a significant reduction in carpal extension was observed in H1 in comparison to the collar (4%; P=0.008), H2 (2%; P=0.005) and H3 (4%; P=0.005). Conclusions: Differences in canine locomotion were observed between conditions in comparison to when the dog was at walk in the collar. Our findings suggest the harness handle type may result in the TL kinematic changes observed. Significant TL SL and ROM restrictions were noted in H1, the only harness in the study with a specific handle design (B-handle type). The increase in proximal TL joint ROM and a subsequent reduction in distal TL joint ROM suggests an alteration to the energy efficiency of locomotion when compared to previous literature. These results were seen only in H1 and not H2, a similar design of harness, therefore suggesting the B-handle type may be the key factor in the kinematic changes observed.
... Compulsory dog leash laws have been implemented worldwide to protect wildlife (Bowes et al., 2017), reduce disease transmission , prevent dog attacks and dog involvement in traffic accidents on roads (Thompson, 1997;Klainbart et al., 2018). Therefore, training dogs to walk loosely on a leash is becoming increasingly important, because a tense leash may compress the trachea and damage their eyes through increased intraocular pressure (Pauli et al., 2006). ...
Human personality influences the way people interact with dogs. This study investigated the associations between the personality of animal shelter volunteers and behavior during on-leash walks with shelter dogs. Video recording and a canine leash tension meter were used to monitor the on-leash walking. Personality was measured in five dimensions (neurotic, extroverted, open, agreeable and conscientious) with the NEO Five-Factor Inventory (NEO-FFI). Neurotic volunteers pulled the leash harder and tended to interact with dogs using more body language; dogs being walked by neurotic volunteers in turn displayed more lip-licking and body shaking and were more likely to be rated as well-behaved. Extroverted volunteers were associated with stronger maximal leash tension at both the human and dog ends of the leash, and they praised the dog more, often in a high pitched voice. These volunteers eliciting more tail-wagging and body shaking by the dog. Extroverted volunteers were also more tolerant of different dog behaviors. Volunteers with personalities characterized by “openness to experiences” were less likely to verbally attract the attention of dogs, praise dogs and talk to them in a high-pitched voice; however, dogs walked by these volunteers were more likely to pull on the leash, and engaged in more lip-licking but less sniffing. “Agreeable” volunteers liked to verbally attract the attention of the dogs and more commonly initiated hand gestures and physical contact, causing the dogs to pull less frequently; dogs in these dyads displayed more gazing and lip-licking behaviors. Conscientious volunteers were less likely to pull the leash and tended to have more physical contact with the dogs but did not favor verbal communication and did not use a high pitched voice.
... However, leash reactivity is one of the most common problems in shelter dogs [37]. Dogs often lunge forwards during on-leash walks, which may damage the soft tissue around the neck and trachea [38] and contribute to increased intraocular pressure [39]. In addition, leash reactivity is reported to be a common problem after adoption [37] and is related to the failure of dog ownerships [40]. ...
Inappropriate leash reactivity is one of the most common problems in shelter dogs, which negatively affects the health of dogs and reduces their adoptability. We explored 370 human-dog interactions, involving 74 volunteers and 111 dogs, in an animal shelter when volunteers walked shelter dogs on a leash, considering the effects of canine demographics and the results of the shelter’s canine behavioural assessments. The interaction was video recorded and coded using ethograms, and a leash tension meter was used to measure the pull strength of dogs and handlers. Results showed that dogs that were more relaxed during the shelter assessment (i.e., when socialising with humans or being left alone in a new environment) were less reactive on the leash, with lower tension and pulling frequency. Moreover, socialised and relaxed dogs displayed more positive body language, such as tail in a high position, gazing at the handler, and exploring the environment. When walking with these dogs, volunteers utilised fewer verbal cues and body language during the walk. In addition to the canine behaviour assessment, there were correlations between canine demographics and the behavioural interaction and humans’ perception. Finally, volunteers perceived the walk as less satisfactory when they needed to pull the leash harder during the walk. This research suggests that the RSPCA behavioural assessment may be useful in predicting the behaviour of shelter dogs when walked by volunteers.
... 20 Additionally, the effect of neck flexion and/or jugular compression during strenuous manual positioning with the eyes above heart level may have contributed to the insignificant difference in IOP observed between the highest pad-supported head position (+20 cm above NP) and the AHL position. Jugular compression during handling has been shown to increase canine IOP, 23,24 though only statistically significant changes were observed with bilateral jugular compression versus ipsilateral compression. 23 The lack of a significant difference observed between the HP + 20 cm and AHL positions suggests it may not be necessary to exert additional physical effort to maintain the head at the latter position in an attempt to minimize increases in IOP. ...
Objective
To evaluate changes in intraocular pressure (IOP) with variable head position in healthy, anesthetized horses in hoisted inversion and to assess the influence of various cofactors (age, sex, body weight, body condition score, and neck length) on IOP changes during hoisting.
Animals studied
Seventeen healthy adult horses without significant ocular abnormalities.
Procedures
Subjects were administered intravenous xylazine/butorphanol premedication and ketamine/midazolam induction with xylazine/ketamine boluses for anesthetic maintenance. While hoisted, IOP was measured in triplicate for each eye via rebound tonometry (TonoVet) at neutral head position (ie, eyes level with the withers), at multiple 5 cm increments above and below neutral (−20 cm through +20 cm) using foam pads for head support, and with eyes above heart level via manual support.
Results
In hoisted positions, IOP ranged from 18 to 51 mmHg. Intraocular pressure significantly decreased with head position elevated ≥+15 cm from neutral and significantly increased when lowered ≤−5 cm from neutral. Neck length significantly influenced IOP (P = .0328) with linear regression indicating a median (range) increase of 0.244 (0.034‐0.425) mmHg in IOP for every 1 cm increase in neck length. Age, sex, breed, body weight, body condition score, and eye (OD vs OS) did not significantly influence IOP. Intraocular pressure only varied significantly between eyes at +10 cm above neutral (OS > OD, 1.7 ± 0.6 mm Hg, P = .0044).
Conclusions
Intraocular pressure in healthy, anesthetized horses varies with head position during hoisting; increased neck length may be associated with larger changes in IOP during hoisting.
... Mandatory dog leash laws have been implemented in many countries around the world to protect wildlife [14], reduce disease transmission [15], prevent dog attacks and dog involvement in road traffic accidents [16,17]. There is a growing emphasis on the importance of loose leash heelwork, as a tense leash can be detrimental to the health of dogs by damaging their trachea and having negative effects on their cornea and intraocular pressure [18]. However, research about human-dog interactions when dogs are walked on a leash is limited. ...
Previous studies have indicated that human gender and canine sex influences human–dog interactions. However, the majority of studies have considered the interaction when dogs were off-leash and the behavioural interactions when dogs are walked on a leash have not been addressed. This study investigated human–dog interactions when shelter volunteers take shelter dogs for an on-leash walk. Video records were made of 370 walks, involving 74 volunteers and 111 shelter dogs, and a leash tension meter was used to determine the pull strength of dogs and walkers. Human gender and canine sex had dyadic effects during the walk. Male dogs tended to pull more frequently and created increased leash tensions. Dogs displayed more stress related behaviours when interacting with men than women, with the signs being spending less time holding the tail in the high position, and more frequent gazing and lip-licking behaviours. Finally, there was a greater pre-disposition in women to use verbal commands, and language typically used with babies, while men were more inclined to have physical contact with dogs. This study’s results may be used to match shelter dogs with appropriate men and women volunteers for walking exercise of the dog, and to improve potential dog socialisation efforts by shelters.
... STT was measured at 30 (T 30 ) and 60 (T 60 ) min after treatment, then every 2 hours during the 12-hour period, and then at 24 (T 24h ) and 36 (T 36h ) hours after application. During all measurements, the animals were handled gently to avoid any tension on the animal's neck which might influence IOP (Pauli et al., 2006). All tonometric measurements were performed by the same person employing rebound tonometry with the Tonovet tonometer (TonoVet®, Tiolat Ltd. ...
Background:
Cyclopentolate is not commonly used as mydriatic drug in veterinary medicine because of limited data on the local and systemic effects in animals.
Aim:
To determine the effects of topical 1% cyclopentolate hydrochloride on intraocular pressure (IOP), horizontal pupil diameter (HPD) and tear production in the cat and rabbit's eye during the first hour and up to 36 hours after treatment.
Methods:
One drop of 1% cyclopentolate hydrochloride was used in the left eye in 10 clinically and ophthalmologically healthy domestic cats and 10 rabbits. IOP and HPD were recorded every 5 minutes during the first hour, then every 2 hours during the following 12-hour period, and at 24 and 36 hours after application. Schirmer tear test (STT) was measured at 30 and 60 minute after treatment, then in same time points as IOP and HPD. Rebound tonometer (TonoVet®) was used to assess IOP, Jameson calliper to measure HPD and STT to determine the tear production.
Results:
1% cyclopentolate increased IOP in cats, reaching a maximum (28.1 ± 5.4 mmHg) at T50 and in rabbits at T25 (16.7 ± 1.3 mmHg). Maximal mydriasis in cats was observed at T40 and lasted 24-36 hours, but in rabbits at T25, and returned to pre-treatment values at T10h-T12h. In cats, STT decreased in both eyes 30 minutes after treatment and remained lower throughout the 36-hour period. In rabbits, STT decreased in the treated eye 30 minutes after treatment, but all following STT measurements returned to normal pre-treatment levels.
Conclusion:
Study showed novel data about the effects of 1% cyclopentolate to IOP, HPD, STT in cats and rabbits. Cyclopentolate in cats caused mydriasis 20-40 minutes after the treatment by increasing IOP, at the same time, pupil diameter reached pre-treatment values 24-36 hours after treatment. In rabbit's mydriasis occurred faster, 10-25 minutes after treatment without significant IOP increase and mydriasis lasted 10-12 hours. Significant STT decrease was recorded in cats, but more likely were connected to stress factors. This drug could be considered as a therapeutical alternative in rabbit more than in cats.
... 22 Care was also taken to avoid exertion of excessive pressure on the globes, which could likewise affect IOP. 23 The same investigator (SJ) obtained all measurements to minimize variation in measurements over time. ...
OBJECTIVE : To assess changes in pupil size and intraocular pressure (IOP) following topical application of a 0.5% tropicamide solution in the eyes of healthy butorphanol-sedated dogs.
ANIMALS : 12 healthy adult Beagles.
PROCEDURES : In a randomized crossover study consisting of 2 treatment periods with a 1-week washout between periods, dogs received an IM injection of butorphanol (0.2 mg/kg) or an equal volume of sterile saline (0.9% NaCl) solution. For each dog, 1 drop of 0.5% tropicamide ophthalmic solution was topically instilled in one eye and 1 drop of artificial tear solution was topically instilled in the other eye 10 minutes after the IM injection and again 5 minutes later. Extent of sedation, pupil size, and IOP were evaluated from 20 minutes before to 80 minutes after the IM injection and compared among treatment combinations.
RESULTS : Butorphanol induced mild (n = 9) or moderate (3) sedation in all dogs and slightly delayed the onset of, but did not prevent, tropicamide-induced mydriasis. Butorphanol caused a significant increase in IOP, which was not exacerbated by tropicamide-induced mydriasis; however, that increase was generally not sufficient to exceed the upper limit of the IOP reference range.
CONCLUSIONS AND CLINICAL RELEVANCE : Results indicated that butorphanol did not prevent tropicamide-induced mydriasis but did increase the IOP in ophthalmologically normal Beagles. Although the butorphanol-induced increase in IOP did not appear clinically relevant for the dogs of this study, that may not be true for dogs with glaucoma, and care should be taken when butorphanol is administered to such dogs.
... In this study, there was no correlation between the age of dogs and the measured intraocular pressure except between the age of dogs and the intraocular pressure of the control eye before the beginning of the irrigation (r= -0.6795). The lack of association between age of dogs and IOP in this study was consistent with the results of a previous study, which was conducted by Pauli et al. (2006). This variation of results may be attributed to first, the tool used for measurement of IOP in each study. ...
here are numerous agents that have been used for irrigation of the ocular tissue from attached foreign bodies, inflammatory exudate and microorganisms. For evaluation of four agents of these irrigation solutions, sixteen clinically healthy dogs of both sexes were used in this study. The dogs were allocated into four equal groups. The right eye of dogs for each group was irrigated 3 times daily for three successive days. The groups were irrigated as following: The first group: ringer’s lactate, the second group: normal saline 0.9%, the third group: boric acid 2% and sodium bicarbonate 1% was used for the fourth group. The left eye was considered control one. The results revealed that the four solutions did not cause any obvious alteration of the eyes and change the intraocular pressure (IOP). According to their effects on the total bacterial count, the four irrigation solutions had not any significant effect. It could be concluded that all of these agents may be used for irrigation of the intact eye and removal of the attached exudate and foreign bodies.
... Of note, proparacaine solution is usually recommended in the veterinary practice due to its predictability and minor side effects during measurement of IOP values [26]. In our study, to obtain an accurate IOP value, donkeys' heads were kept in a normal and upright position following the previously described precautions [1,2,27]. Table 2 Respiratory rate (breath/min) after intravenous administration of medetomidine (0.007 mg kg À1 ), tramadol (2 mg kg À1 ), medetomidine/tramadol combination (0.007 mg kg À1 and 2 mg kg À1 , respectively), and 0.9% normal saline (10 mL) in clinically healthy donkeys. ...
... All birds in the study tolerated the measurement of IOP without the need for general anesthesia or forceful restraint. We avoided the use of excessive pressure on the cervical region, so that no abrupt changes would be induced in venous return and consequent increase in IOP in an iatrogenic way (Pauli et al. 2006). ...
The aim of this study was to establish reference values for selected ophthalmic diagnostic tests in healthy blue-and-yellow macaws. We investigated a total of 35 adult macaws (70 eyes) of undetermined sex and with an average weight of 1 kg, who were living in captivity in the Federal District, Brazil. Tear production using the Schirmer tear test (STT), normal conjunctival flora, intraocular pressure (IOP) using a rebound tonometer and horizontal palpebral fissure length (HPFL) were evaluated. In this study, 84.1% of samples were positive for microbial growth. Bacteria, fungi and yeasts were isolated, and Staphylococcus spp. (21.9%) and Bacillus spp. (26.8%) were the most frequently isolated microorganisms. The mean value for STT was 7.6±4.6mm/min in the right eye (OD) and 6.6±4.4mm/min in the left eye (OS) (median = 7,11±0,76mm/min). Mean IOP was 11.4±2.5mm Hg OD and 11.6±1.8mm Hg OS (median = 11.49±0.22mm Hg), prior to anesthesia, and 7.6±2.4mm Hg OD and 7.8±1.8mm Hg OS (median 7.71±0.08mmHg) after anesthesia. The IOP was significantly lower when the animals were under anesthesia as compared to when they were conscious (p≤0.05). Horizontal palpebral fissure length was 11.7±0.1mm OD and 11.8±0.1mm OS (median = 11.72±0.07mm). The STT showed a positive correlation with palpebral fissure measurement for this species. These selected ophthalmic reference values will be particularly useful in diagnosing pathological changes in the eyes of blue-and-yellow macaws.
... After treatment, IOP and HPD were recorded every five minutes in both eyes (T5; T10; …T60/65). During all measurements, the animals were handled gently to avoid any tension on the animal's neck which might influence IOP neck (Pauli et al., 2006). All tonometric measurements were performed by the same person employing rebound tonometry with the Tonovet tonometer (TonoVet®, Tiolat Ltd. ...
The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically normal canine patients (between the ages of 2 and 6 years) of varying breed and sex were used in this study. Animals were randomly divided into four groups of ten and given one drop of tropicamide, atropine, phenylephrine or saline into one eye. IOP and HPD were measured in both eyes every 5 minutes for 60 minutes. Tropicamide increased IOP by 8.8±4.0 mmHg 35 minutes post-treatment compared to pre-treatment (P<0.01) only in treated eye. IOP in the contralateral eye did not increase. With atropine the maximum increase in IOP was 2.6±2.8 mmHg at 20 minutes post treatment in the treated eye (P<0.01). IOP in the contralateral eye did not increase. Phenylephrine increased IOP by 2.3±2.1 mmHg (P<0.05) 10 minutes after treatment. Also in the untreated eye IOP increased by 2.3±2.1 mmHg, 20 minutes post-treatment. Maximum HPD in eyes treated with tropicamide occurred at 55 minutes and with atropine at 60 minutes. There were no HPD changes in the contralateral, untreated eye. Topical 10% phenylephrine showed maximal pupil dilation 60 minutes after treatment, but the HPD of the – untreated eye slightly decreased at 15 minutes, but this change only reached statistical significance at 40 min post- treatment (P<0.05). Normal saline showed no influence on IOP or HPD. The drugs investigated here show a significant increase in IOP after mydriatics.
... After treatment, IOP and HPD were recorded every five minutes in both eyes (T5; T10; …T60/65). During all measurements, the animals were handled gently to avoid any tension on the animal's neck which might influence IOP neck (Pauli et al., 2006). All tonometric measurements were performed by the same person employing rebound tonometry with the Tonovet tonometer (TonoVet®, Tiolat Ltd. ...
The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically normal canine patients (between the ages of 2 and 6 years) of varying breed and sex were used in this study. Animals were randomly divided into four groups of ten and given one drop of tropicamide, atropine, phenylephrine or saline into one eye. IOP and HPD were measured in both eyes every 5 minutes for 60 minutes. Tropicamide increased IOP by 8.8±4.0 mmHg 35 minutes post-treatment compared to pre-treatment (P<0.01) only in treated eye. IOP in the contralateral eye did not increase. With atropine the maximum increase in IOP was 2.6±2.8 mmHg at 20 minutes post treatment in the treated eye (P<0.01). IOP in the contralateral eye did not increase. Phenylephrine increased IOP by 2.3±2.1 mmHg (P<0.05) 10 minutes after treatment. Also in the untreated eye IOP increased by 2.3±2.1 mmHg, 20 minutes post-treatment. Maximum HPD in eyes treated with tropicamide occurred at 55 minutes and with atropine at 60 minutes. There were no HPD changes in the contralateral, untreated eye. Topical 10% phenylephrine showed maximal pupil dilation 60 minutes after treatment, but the HPD of the – untreated eye slightly decreased at 15 minutes, but this change only reached statistical significance at 40 min post- treatment (P<0.05). Normal saline showed no influence on IOP or HPD. The drugs investigated here show a significant increase in IOP after mydriatics. © 2017, Faculty of Veterinary Medicine, University of Tripoli and National Authority for Scientific Research. All rights reserved.
... Some dogs may pull against pressure such as that exerted by a collar. The resulting pressure on the neck can damage the larynx or trachea, and also significantly increases intraocular pressures [7,8]. Therefore, leash pulling may be not only annoying, but harmful to both humans and dogs. ...
Dogs are relinquished to shelters due to behavioral problems, such as leash pulling and jumping up. Interomones are chemical cues produced by one species that elicit a response in a different species. We reported earlier that androstenone, a swine sex pheromone, acts as an interomone to reduce barking in dogs. Here we report two models using 10 dogs/study: a dog jumping and a dog walking model. For the leash-pulling model, each time the dog pulled on the leash the walker either did nothing (NOT), or sprayed the dog with water (H₂O), androstenone + water (ANH), androstenone 0.1 µg/mL (AND1), or androstenone 1.0 µg/mL (AND2). The number of pulls during each walk was counted. For the jumping up model, each time the dog jumped the researcher did nothing (NOT), or sprayed the dog with H₂O, ANH, AND1, or AND2. The number of jumps and the time between jumps were recorded. In Study 1, ANH, AND1, and AND2 each reduced leash pulling more than NOT and H₂O (p< 0.01). In Study 2, all treatments were effective in reducing jumping up behavior. Androstenone reduced jumping up, but not beyond that elicited by a spray of water alone. We conclude that androstenone in multiple delivery vehicles reduced leash pulling. The burst of air intended as a disruptive stimulus in the correction sprays may be too harsh for more sensitive dogs, and as such use of these sprays is cautioned in these animals. For other dogs, this interomone can be used to stop some behavior immediately or as a part of a training program to reduce undesirable behavior.
... An acclimation period of at least 5 days is recommended based on our findings, to minimize the influence of patient-related factors such as stress on the IOP measurements. It is well documented in the veterinary literature that lack of patient cooperation and other external factors, such as pressure on the neck, traction on the eyelids, and body position, can have a significant impact on IOP measurements (Pauli et al., 2006;Broadwater et al., 2008;Klein et al., 2011a,b). Our study confirmed this experience in a group of research Beagles previously unaccustomed to the type of handling and restraint necessary for IOP measurements. ...
The aim of this study was to determine the effect of oral administration of carprofen on intraocular pressure in normal dogs. Twelve young adult beagle dogs were randomly assigned to treatment (n = 6) or control (n = 6) groups. After an 11-day acclimation period, the treatment group received approximately 2.2 mg/kg carprofen per os every 12 h for 7 days, and the control group received a placebo gel capsule containing no drug per os every 12 h for 7 days. Intraocular pressure (IOP) was measured by a rebound tonometer at three time points per day (8 am, 2 pm, and 8 pm) during the acclimation (days 1-11) and treatment (days 12-18) phases and for 48 h (days 19-20) after the completion of treatment. There was no statistically significant change in IOP for either eye in the dogs receiving oral carprofen during the treatment phase (days 12-18). After day 4, no significant daily IOP changes were seen in control group dogs. Carprofen administered orally every 12 h for 7 days had no effect on IOP in normal beagle dogs. An acclimation period to frequent IOP measurements of at least 5 days is necessary to establish baseline IOP values and minimize possible anxiety-related effects on IOP measurements.
... Rebound tonometry allows quick, easy, and hygienic measurement of IOP 23 and can be performed without animal restraint, which avoids potential measurement artifacts caused by the stress of handling or the inadvertent application of excessive pressure to the head or neck. 4,24 Although most of the bearded dragons of the present study had signs of slight discomfort associated with the intense bounce of the tonometer tip on the cornea, fluorescein staining after tonometry was completed did not reveal any evidence of corneal damage. The tip of a rebound tonometer specifically designed for use in rodents has a slightly smaller diameter (1 to 2 mm), compared with that of the rebound tonometer used in the present study, and may have elicited less reaction from the bearded dragons. ...
Objective:
To evaluate the use of rebound and applanation tonometry for the measurement of intraocular pressure (IOP) and to assess diurnal variations in and the effect of topical anesthesia on the IOP of healthy inland bearded dragons (Pogona vitticeps).
Animals:
56 bearded dragons from 4 months to 11 years old.
Procedures:
For each animal following an initial ophthalmic examination, 3 IOP measurements were obtained on each eye between 9 AM and 10 AM, 1 PM and 2 PM, and 5 PM and 7 PM by use of rebound and applanation tonometry. An additional measurement was obtained by rebound tonometry for each eye in the evening following the application of a topical anesthetic to evaluate changes in the tolerance of the animals to the tonometer. Descriptive data were generated, and the effects of sex, time of day, and topical anesthesia on IOP were evaluated.
Results:
Bearded dragons did not tolerate applanation tonometry even following topical anesthesia. Median daily IOP as determined by rebound tonometry was 6.16 mm Hg (95% confidence interval, 5.61 to 6.44 mm Hg). The IOP did not differ significantly between the right and left eyes. The IOP was highest in the morning, which indicated that the IOP in this species undergoes diurnal variations. Topical anesthesia did not significantly affect IOP, but it did improve the compliance for all subjects.
Conclusions and clinical relevance:
Results indicated that rebound tonometry, but not applanation tonometry, was appropriate for measurement of IOP in bearded dragons. These findings provided preliminary guidelines for IOP measurement and ophthalmic evaluation in bearded dragons.
... No pressure was applied on the neck area during manipulation. 14 For quantification of aqueous tear production, a standardized STT strip was used (Schirmer Tear Test â , MSD Animal Health, Boxmeer, The Netherlands) (Fig. 1a). For measurement of the STT1, the strip was placed in the ventrolateral part of the conjunctival sac for 60 s and the result was noted immediately after removal of the strip. ...
Objective
The aim of this study was to investigate the development of aqueous tear production and intraocular pressure in healthy canine neonates between 2 and 12 weeks of age.AnimalsOne litter, consisting of 8 healthy Beagle dogs—four males and four females—was used.ProceduresBetween the age of 2 and 12 weeks, tear production and intraocular pressure were measured weekly in both eyes. Tear production was measured by Schirmer tear test, before (STT1) and after (STT2) topical anesthesia and drying of the conjunctival sac. Intraocular pressure (IOP) was measured using a rebound tonometer. As no significant differences existed between left and right eye measurements (STT1, STT2, and IOP) at all time points, only right eye measurements were further analyzed.ResultsSTT1, STT2, and IOP values increased significantly until the age of 9 weeks for STT1, until the age of 10 weeks for STT2, and until the age of 6 weeks and again between 10 and 11 weeks of age for IOP. IOP decreased significantly between 11 and 12 weeks of age. There were no significant differences in STT1, STT2, and IOP between males and females, except for IOP at 10 and 12 weeks of age. No significant correlation was demonstrated between body weight and STT1 or STT2.ConclusionsSTT1, STT2, and IOP values increased significantly in the first weeks after birth. The results of this study indicate that separate reference values for tear production and intraocular pressure need to be established for neonatal dogs.
... 51 The camels were gently restrained in the sitting position to avoid variations in IOP caused by head position, 40,53 and care was taken to avoid excessive manipulation of the eyelids or pressure on the neck, which could falsely increase IOP measurements. 54 The age of the camels in the present study ranged from 1 to 10 years, and the reason the mean IOP for camels in the mature group (age, ≥ 5 years) was significantly lower than that for the camels in the immature group (age, < 5 years) is unknown. The decrease in IOP with age might be a consequence of a reduction in active secretion of aqueous humor associated with declining systemic health. ...
Objective:
To determine the intraocular pressure (IOP) in healthy dromedary camels (Camelus dromedarius).
Animals:
24 clinically normal dromedary camels.
Procedures:
For each camel, the IOP of both eyes was measured with applanation tonometry. Three measurements with < 5% variance were obtained for each eye on the same day of the week for 3 consecutive weeks. Mean IOP was calculated for each eye on each day for comparison purposes.
Results:
Mean ± SD IOPs for the right (31.1 ± 2.1 mm Hg) and left (30.8 ± 1.9 mm Hg) eyes of immature camels were significantly higher than those for the right (27.1 ± 1.2 mm Hg) and left (28.2 ± 1.2 mm Hg) eyes of mature camels. Intra-assay and interassay coefficients of variation (CVs) for IOP measurements of the right and left eyes did not differ significantly between immature and mature camels. Interassay CVs of IOP measurements for the right and left eyes ranged from 1.5% to 12.1% and 1.2% to 10.3%, respectively, for immature camels and from 1.2% to 17.2% and 1.7% to 18.8%, respectively, for mature camels. Intra-assay CVs of IOP measurements for the right and left eyes ranged from 1.5% to 10.6% and 1.9% to 9.6%, respectively, for immature camels and from 2.8% to 16.9% and 2.7% to 12.4%, respectively, for mature camels. Age was negatively correlated (r = -0.403) with IOP.
Conclusions and clinical relevance:
Results provided a reference and might aid in the diagnosis of glaucoma and uveitis during complete ophthalmic examinations of dromedary camels.
... Best practice often has more to do with technique than equipment, but collars that offer a softer interface between the trainer and the dog are generally more forgiving and reduce the impact of excessive force or poor timing, so are favoured from a welfare perspective. Training techniques involving choke chains, prong collars and even flat collars are capable of mechanical or ischaemic damage to the larynx, oesophagus, thyroid, trachea, brain and increased intraocular pressure (Grohmann et al., 2013;Brammeier et al., 2006;Pauli et al., 2006). Meanwhile, the use of shock (electric) collars remains highly contentious (Ogburn et al., 1998;Haug et al., 2002;Schilder and van der Borg, 2004;Overall, 2007Overall, , 2007bSchalke et al., 2007;Steiss et al., 2007). ...
... The measurements were performed with the dog standing or in sternal recumbency, avoiding any tension on the animal's neck which might influence IOP. 25 After treatment, IOP and HPD were measured every five minutes in both eyes, for a period of 60 min. ...
... Furthermore, special attention was given to minimize any pressure on the neck, especially in the throatlatch region, in order to prevent iatrogenic IOP alterations. 31 ...
Objective:
To evaluate the effect of intravenous administration of romifidine on the intraocular pressure (IOP) in horses.
Animals studied:
Twenty-four horses with no ocular abnormalities.
Procedure:
Horses were randomly assigned into two equal groups (treatment and control). All horses in the treatment group received an intravenous (IV) injection of romifidine (40 μg/kg). The horses in the control group were administrated an intravenous injection of 0.9% saline (0.4 mL/100 kg). In both groups, the IOP values were measured immediately (T0 ) pre-administration and at 5 (T5 ), 15 (T15 ), 30 (T30 ), 45 (T45 ), 60 (T60 ), 90 (T90 ), and 120 (T120 ) min after drug administration.
Results:
The pre-treatment values (T0 ) of IOP for right and left eyes were 24.25 ± 3.5 and 25.16 ± 3.4 mmHg, respectively. A significant decrease in IOP values was observed in both right and left eyes of the horses in treatment group at T5 , T15 , T30 , T45 , T60 , and T90 in comparison with the baseline values (P < 0.05). The lowest level of IOP in romifidine-treated groups was recorded at T45 for the right and left eyes (10.25 ± 2.3 and 11.25 ± 3.5 mmHg, respectively).
Conclusion:
Romifidine significantly decreased IOP in clinically normal horses and may be used safely for surgery or diagnostic ocular procedures in horses when specific control of IOP is required.
... The measurements were performed with the dog standing or in sternal recumbency, avoiding any tension on the animal's neck which might influence IOP. 25 After treatment, IOP and HPD were measured every five minutes in both eyes, for a period of 60 min. ...
To compare the effects of topical 1% atropine sulfate and systemic 0.1% atropine sulfate on the intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the canine eye.
Four groups, each containing 10 dogs of varying age, breed, and sex were treated as follows: (i) One 30 μL drop of topical 1% atropine sulfate was applied unilaterally in each dog, (ii) A control group, one drop of 0.9% saline was used, (iii) 0.06 mg/kg atropine sulfate was given by intramuscular injection, and (iv) Control with saline injected intramuscularly. In all groups, IOP and HPD were measured every 5 min over 60 min.
Topical atropine significantly increased IOP in the treated eye with no change in the untreated eye. A maximum increase in IOP from 17.7 ± 3.1 to 20.3 ± 3.1 mmHg (14.7% increase) was obtained 23.0 ± 14.3 min post-treatment. Maximal HPD of 12.1 ± 1.7 mm in the treated eye occurred 46.5 ± 6.3 min after treatment, with no increase in the untreated eye. Systemic atropine caused an increase in IOP in both eyes, showing a maximum at 15.5 ± 10.6 min post-treatment with an IOP of 17.3 ± 4.6 mmHg in the right eye and 17.1 ± 5.2 mmHg in the left eye (21.8% increase in the right eye and 21.6% in the left eye). Maximal HPD was noted in both eyes 30.0 ± 11.6 min after treatment.
Atropine sulfate causes a significant increase in IOP when given both topically and by intramuscular injection. It should be used with caution, or indeed avoided entirely, in dogs with glaucoma or in those with a predisposition to the condition.
... Dog handlers in favor of this technique still believe that its correct application "takes the drive and fight out of the dog" and does not cause any pain (Leerburg, 2010). It has been widely recognized by most veterinary behavior specialists that this form of punishment should be avoided as it causes fear and brings about an escalation of defensive aggression and increasing intraocular pressure (Hetts, 2000;Pauli et al., 2006;AVSAB, 2012). Furthermore, choke chains and collars can cause mechanical or ischemical damage to the larynx, esophagus, thyroid, or trachea (Brammeier et al., 2006). ...
The features of severe ischemic brain damage after strangulation by the owner of a 1-year-old German shepherd dog are described. The dog was disciplined by the owner during training by holding the dog off the ground by his choke chain collar. At first, the dog behaved normally, but he became increasingly ataxic and started circling to the left and showed reduced consciousness. The neurological examination revealed severe disorientation, left lateral pleurothotonus, and circling. The neurological findings were consistent with a multifocal brain lesion. A magnetic resonance imaging scan was performed and showed changes in the T2- and diffusion-weighted images, consistent with severe cerebral edema resulting from ischemia. Because of the severity of the clinical features, the dog was later euthanized. To the author's knowledge, this is the first report of a severe brain ischemia after strangulation in a dog.
This article provides a review of the required ocular tests during the ophthalmologic examinations of canine and feline patients. Knowledge of medications affecting ocular parameters and awareness of available instrumentation and test materials is essential for accurate diagnoses.
In companion animals, glaucoma is optic nerve damage caused by an elevated intraocular pressure. This results in irreversible blindness as well as ocular pain. Primary glaucoma is a hereditary condition arising from anatomical abnormalities of the iridocorneal angle (goniodysgenesis/pectinate ligament dysplasia). Secondary glaucoma occurs as a sequela to another ophthalmic disease, most commonly uveitis. Glaucoma may develop acutely or insidiously but should be treated urgently in both situations, as there is potential to delay vision loss in some cases. This chapter addresses clinical signs of glaucoma, diagnosis, and short‐term management of glaucoma in dogs and cats.
Objective:
To determine the prevalence of ocular disease in draft horses in the United States.
Animals:
Draft horses of various breeds and ages.
Procedure:
Nondilated ophthalmic examination was performed using slit lamp biomicroscopy and indirect ophthalmoscopy. Intraocular pressures were measured when possible.
Results:
One hundred sixty-five draft horses were examined. Age range: 10 days to 33 years (mean 10.8 years, median 10 years); 87 geldings (52.7%), 71 mares (43.0%), 7 stallions (4.2%); 64 Percherons (38.8%), 51 Belgians (30.9%), 29 Clydesdales (17.6%), 15 Shires (9%), and 6 other draft breed (3.6%). Intraocular pressure: mean 24.7 mmHg OD, range 13-37 mmHg; mean 25.0 mmHg OS, range 11-37 mmHg. Vision-threatening disease was present in 9 horses (5.5%): complete cataracts 1, post-traumatic optic nerve atrophy 1, uveitis and secondary glaucoma 1, retinal detachment 1, large chorioretinal scar 3, phthisis bulbi 2. Non-vision-threatening ocular disease was present in 56 horses (33.9%) involving one or more ocular structures: eyelid trauma/notch defect 14 (8.5%), SCC-type adnexal lesions 12 (7.3%), corneal scars 16 (9.7%), keratitis 6 (3.6%), corpora nigra cyst 15 (9.1%), incipient/punctate cataract 50 (30.3%), vitreous degeneration 10 (6.1%), asteroid hyalosis 1, "bullethole" chorioretinal scars 3, RPE coloboma 1. Linear keratopathy was present in 28 horses (17%) with 2/28 having concurrent vision threatening ocular disease.
Conclusions:
Ocular abnormalities, in particular minor cataracts, were relatively common in this population, but not typically vision-threatening. Additionally, this survey demonstrated a greater prevalence of linear keratopathy in draft horses compared with reports in other breeds; however, it does not appear to be associated with concurrent ocular disease.
OBJECTIVE
To compare single and triplicate applanation tonometry values across previous intraocular pressure (IOP) studies in dogs.
ANIMALS
116 ophthalmologically normal dogs.
PROCEDURES
Triplicate IOP readings (n = 1432) from studies evaluating effect of anesthetic protocols were analyzed to estimate a range of probable differences between averaged triplicate and first, averaged and lowest, and first and lowest IOPs. The decrease in variability with triplicate measurements and the magnitude of effects on statistical power were quantified.
RESULTS
The 2.5th to 97.5th interpercentile range for differences of averaged triplicate values minus first IOP readings was –3 to 2.7 mm Hg; for averaged minus lowest: 0 to 3.7 mm Hg; for first minus lowest: 0 to 5 mm Hg. The 95% prediction interval for differences in study group means (n = 160 groups, n = 5 to 11 eyes per group) based on averaged minus first measurements was –1.0 to 0.9 mm Hg with associated SDs reduced by 4% on average. Analysis of previous studies using averaged instead of first IOP values resulted in minimal decreases in SEs of 3–9% (0.03 to 0.09 mm Hg). Of 11 comparisons found significant with averaged data, 2 (18%) were found nonsignificant with first measurements. Of 96 comparisons found nonsignificant with averaged data, 3 (3%) were found significant with first measurements.
CLINICAL RELEVANCE
With applanation tonometry in ophthalmologically normal dogs, no clinically meaningful difference was found between the first, lowest, or averaged triplicate IOP measurements, but the first reading has a larger variance and hence will result in lower statistical power.
Operational K9s encompass a unique population of working dogs that serve as a force multiplier in various civilian law enforcement, force protection, search and rescue, and humanitarian operations. These elite canines do not volunteer to serve, yet they are some of the most faithful and dependable operators in the field. They undoubtedly perform an invaluable service in today's society and are owed a tremendous debt of gratitude for their selfless service, loyalty, and sacrifices. This article describes the unique characteristics and occupational hazards that pertain to the community of Operational K9s.
Objective:
To determine the effects of gabapentin, tramadol, and meloxicam on tear production, intraocular pressure (IOP), pupillary diameter, tear break-up time, and corneal touch threshold in healthy dogs when given orally for 3 days.
Animals:
9 healthy research Beagles.
Procedures:
A randomized, blinded, case-crossover study with a 6-sequence, 3-treatment, and 3-period design was performed. A 7-day acclimation period was followed by 3 treatment phases, each with a 3-day treatment period followed by a 7-day washout period for 3 different drugs. Block randomization was used to group dogs for treatments with drug A (gabapentin), B (tramadol), or C (meloxicam). Measurements of tear production, IOP, pupillary diameter, tear break-up time, and corneal touch threshold were performed on a schedule. A generalized mixed-effects linear regression model was created for each ocular variable, accounting for repeated measures within individuals.
Results:
Intraocular pressure was the only variable to have differed substantially between the first 5 and last 2 days of the acclimation period. When treatment phase, day, time of day, dog identification, baseline value, and eye were accounted for, the mean IOP was lower for dogs during treatment phases with gabapentin or tramadol, compared with meloxicam, but this difference was not considered clinically meaningful.
Conclusions and clinical relevance:
Results indicated that a minimum 5-day acclimation period is necessary for IOP measurements to return to baseline in dogs. The statistically identified effect of gabapentin and tramadol on IOP in dogs of the present study warrants further investigation. It is possible that at higher dosages, or in dogs with glaucoma, this effect may become clinically significant.
Leash tension forces exerted by dog and handler during walks affect their welfare. We developed a novel ambulatory measurement device using a load cell and a tri-axial accelerometer to record both the tension and direction of forces exerted on the leashes. Data were relayed telemetrically to a laptop for real time viewing and recording. Larger and heavier dogs exerted higher leash tension but had a lower pulling frequency than their smaller and lighter conspecifics. This pattern was observed in the reactional forces of handlers. Young dogs pulled more frequently during walks, which was also mirrored in handlers’ pulling. Well-behaved dogs created lower leash tension, but handlers did not respond with lower forces. This novel method of recording leash tension will facilitate real-time monitoring of the behaviour of dogs and their handlers during walks.
Background
Dog collars have the potential to cause harm when the dog pulls on the lead. This study aimed to determine the effects of collar type and force applied using the lead on the pressure on a simulated neck model.
Methods
Seven collars and a slip lead were tested on a canine neck model. This consisted of a plastic cylinder ‘neck’, with a pressure sensor beneath the collar. A range of forces were applied to the lead representing different interactions: firm pull (40 N), strong pull (70 N) and jerk (mean force 141 N). Contact area of the collar and pressure on the neck were recorded.
Results
Collars exerted a pressure of between 83 kPa and 832 kPa on the model neck. There was a significant effect of collar type (F(7)=25.69, P<0.001) and force applied (F(2)=42.60, P<0.001) on the pressure exerted on the neck. Collar type (χ(7)=64.94, P<0.001), but not force applied (χ(2)=3.20, P=0.202), affected the contact area that the pressure was exerted over.
Conclusion
Variation in the pressures exerted on the neck may have implications on comfort and the potential to cause injury. No single collar tested provided a pressure considered low enough to mitigate the risk of injury when pulling on the lead.
The study aimed to compare the effect of restrictive and non-restrictive harnesses on shoulder extension of dogs at walk and trot. This was a prospective study of nine dogs. Dogs were walked and trotted on a treadmill at a comfortable walking and trotting speed, first with no harness, then with each harness type, with and without added weights. Dogs were filmed and the angle of shoulder extension was measured using non-reflective markers and a video analysis software. Significant decrease in shoulder extension was found with both types of harnesses in comparison with no harness, except for the restrictive harness with weights. Shoulder extension was 2.6° and 4.4° less in dogs wearing a non-restrictive harness than in dogs wearing a restrictive harness, at walk and trot, respectively. The addition of weights did not consistently add more restriction to shoulder extension. The results of this study indicate that harnesses do limit shoulder extension, but perhaps not in the way originally anticipated, as results show extension is significantly reduced under the non-restrictive harnesses compared with the restrictive harnesses, with and without weights.
Objective:
To study the diurnal variation in intraocular pressure (IOP) and central corneal thickness (CCT) in healthy Beagles by rebound tonometry and ultrasonic pachymetry, respectively, in addition to determining whether a correlation exists between these two variables.
Animals studied:
Twenty eyes from 10 healthy Beagle dogs were included in the study.
Procedures:
The IOP and CCT were measured by rebound tonometry and ultrasonic pachymetry, respectively, at 2-h intervals over an 8-hour period between 10:00 and 18:00.
Results:
The mean values (± SD) of IOP obtained were 11.45 ± 2.96 at 10:00, 10.00 ± 1.89 at 12:00, 8.25 ± 1.62 at 14:00, 7.05 ± 1.05 at 16:00, and 6.55 ± 1.36 at 18:00. The mean values (± SD) of CCT obtained were 554.95 ± 72.41 at 10:00, 549.20 ± 69.10 at 12:00, 566.15 ± 80.56 at 14:00, 545.45 ± 70.19 at 16:00, and 538.30 ± 73.33 at 18:00. The IOP and CCT of dogs were found to decrease progressively from the first to the last measurement. There were statistically significant differences between the IOP (P = 0.000) and CCT values (P = 0.032) measured at different times of the day. There was no effect or interaction between gender and eye with the dependent variables. The IOP and CCT were found to be positively correlated (r = 0.213, P = 0.034). The regression equation demonstrated that for every 100 μm increase in CCT, there was an elevation in IOP by 0.8 mmHg.
Conclusions:
The CCT and IOP values were lower in the afternoon/evening than in the morning, and these were positively correlated. Both findings are important for the diagnostic interpretation of IOP values in dogs.
Glaucoma is one of the most challenging ophthalmic conditions to treat. Early recognition and treatment are crucial to prolonging duration of a comfortable, visual eye. Therefore, most of this chapter is devoted to diagnosis of glaucoma (including clinical signs and interpretation of tonometry) and treatment of glaucoma. For the latter, a review of the main classes of antiglaucoma drugs is included, along with descriptions of their use and example situations illustrating glaucoma therapy. Additional tips for daily practice and/or glaucoma management are included. A bibliography lists references for further reading.
The diagnosis of glaucoma is highly dependent on a working understanding of the clinical signs and available diagnostic procedures. Clinical signs may be attributable to increased intraocular pressure and/or complex alterations in the physiology or molecular biology of the anterior segment, retinal ganglion cells, and optic nerve. Many diagnostic procedures seek to more fully characterize these alterations and to identify which clinical features increase the risk of overt primary angle closure glaucoma (PACG) occurring. Considerable progress has been made in identifying the anatomic features that predispose an eye to PACG, and in elucidating the role of reverse pupillary block.
Introduction
Management of the ophthalmic surgical patient is a team effort with veterinary nurses, veterinary surgeons and owners all playing vital roles in ensuring a successful outcome. The role of the veterinary nurse extends from ensuring careful and appropriate restraint of the ophthalmic patient pre surgery to monitoring post-operative analgesia. Nursing the surgical ophthalmic patient requires specific considerations and often has rewarding outcomes.
Objective
To determine the central corneal thickness (CCT) by ultrasonic pachymetry and the effect of these values on the measurements of intraocular pressures (IOP) with rebound tonometry (TonoVet®) in a captive flock of black-footed penguins (Spheniscus dermersus). Variations in CCT by age and weight, and variations in IOP by age were compared.Animal studiedBoth eyes of 18 clinically normal black-footed penguins (Spheniscus dermersus) were used.ProcedureThe IOP was measured by the TonoVet® in both eyes of all the penguins. CTT measurements were performed 5 min later in all eyes using an ultrasound pachymeter.ResultsThe mean IOP values ± SD were 31.77 ± 3.3 mm Hg (range of mean value: 24–38). The mean CCT values were 384.08 ± 30.9 μm (range of mean value: 319–454). There was no correlation between IOP and CCT values (P = 0.125). There was no difference in CCT measurements by age (P = 0.122) or weight (P = 0.779). A correlation was observed (P = 0.032) between IOP values and age. The coefficient of correlation was negative (ρ = −0.207).Conclusions
Ultrasound pachymetry has shown to be a reliable and easy technique to measure CCT in penguins. No correlation was observed between IOP and CCT values in this study. IOP showed a significant but weak decrease as age increased in the black-footed penguin.
Recognize, diagnose, and manage a vast range of common and important ocular conditions with the latest edition of this trusted reference. Extensively revised and updated by a team of internationally respected contributors, this edition provides a comprehensive, yet practically oriented, diagnostic guide to ophthalmic disease, covering structure and function, ocular development, pathology, examination and diagnosis, pharmacology, and emergency management for a wide variety of small and large animal species. Clinical focus addresses vital information for evaluating, diagnosing, managing, and monitoring patients. Logical organization based on anatomic region makes information easy to locate. Fully updated diagnostic methods, pharmacologic therapies, and surgical procedures help you provide the most current, effective care. Extensively updated content reflects the clinical expertise of three new, internationally respected veterinary ophthalmologists. Full-color format with over 1000 photographic images and step-by-step, illustrated procedures helps you recognize, diagnose and treat ocular conditions medically and surgically. A new chapter on the ophthalmology of birds and other exotic species provides expert guidance in the care of these increasingly popular companion species. A new chapter on ocular manifestations of systemic disease in large and small animals helps you utilize the ophthalmologic examination to more accurately diagnose and treat diseases and disorders affecting other body systems. Hardcover format adds durability for frequent reference.
To investigate the response of choroidal blood flow in the foveal region of the human eye to increases in mean perfusion pressure (PPm = mean ophthalmic artery pressure - intraocular pressure; IOP) induced by isometric exercises.
Using laser-Doppler flowmetry, changes in velocity (ChBVel), number (ChBVol), and flux (ChBF) of red blood cells in the choroidal vascular system in the foveal region of the fundus were measured in both eyes of 11 normal subjects (ages 18 to 57 years) during isometric exercises.
During 90 seconds of squatting, PPm increased by an average of 67%, from 46 to 77 mm Hg. This resulted in a significant increase of 12% in ChBFm (the mean of ChBF during the heart cycle), mainly caused by an increase in ChBVelm. A further increase in PPm to a value approximately 85% above baseline resulted in a 40% increase in ChBFm. A significant negative correlation was found between the changes in ChBVelm and ChBVolm, during squatting.
Previous studies have demonstrated that during isometric exercise, blood pressures in the ophthalmic and brachial arteries rise in parallel. These observations and the current results indicate that an increase in PPm up to 67% induces an increase in choroidal vascular resistance that limits the increase in choroidal blood flow to approximately 12%. This regulatory process fails when PPm is further increased.
To evaluate the effect of a tight necktie on intraocular pressure (IOP) measurement using Goldmann applanation tonometry.
40 eyes of 20 normal subjects and 20 open angle glaucoma patients (all male) were enrolled. IOP was measured with an open shirt collar, 3 minutes after placing a tight necktie, and 3 minutes after loosening it. All measurements were made by the same examiner.
Mean IOP in normal subjects increased by 2.6 (SD 3.9) mm Hg (p=0.008, paired t test; range -3 to +14 mm Hg) and in glaucoma patients by 1.0 (1.8) mm Hg (p=0.02, paired t test; range -2 to +4.5 mm Hg). In normal subjects, IOP in 12 eyes was increased by >/=2 mm Hg and in seven eyes by >/=4 mm Hg. In glaucoma patients, IOP in six eyes was increased by >/=2 mm Hg and in two eyes by >/=4 mm Hg.
A tight necktie increases IOP in both normal subjects and glaucoma patients and could affect the diagnosis and management of glaucoma.
The high metabolic rate of the human retina is supported by the choroidal vasculature. Knowledge of the normal choroidal blood flow (ChBF) responses to various physiological stimuli is therefore highly important if the pathophysiology of ocular diseases involving the choroid is to be understood better. In the present study, the hemodynamic responses of the subfoveal ChBF were examined during and after an exercise-induced increase in the ocular perfusion pressure (OPP).
Twenty-six healthy volunteers, 19 to 55 years of age participated in this two-phase study. Each subject increased resting OPP through stationary biking at a heart rate (HR) of 140 beats per minute (bpm) over 20 minutes. The ChBF was measured by laser Doppler flowmetry (LDF), the systemic BP by electronic sphygmomanometry, and the resting intraocular pressure (IOP) by applanation tonometry.
The OPP increased by approximately 43% at the onset of biking, and then decreased biphasically to approximately 12% above resting value by the end of biking. The ChBF remained within 10% of its basal value throughout biking. Immediately after biking, the OPP decreased twice as much as the ChBF in the same time frame.
The dissociation between the OPP and the ChBF during biking and recovery suggests that some mechanism keeps the ChBF close to its basal value, an observation that indicates blood flow regulation.
Intraocular pressure was artificially elevated for eight hours in eight owl monkeys. The first permanent effect (produced at a perfusion pressure of plus 15 mm Hg) was partial necrosis of iris stroma and ciliary processes, associated with microscopic lesions in the photoreceptors and retina pigment epithelium around the disc and in the retinal periphery. At a slightly higher pressure, visual nerve fibers in the retina and optic nerve and their ganglion cells were affected. Simultaneously, the outer retinal layers showed damage to the pigment epithelium, photoreceptors, and other nuclear layers. At even higher pressures, nearly all the other intraocular tissues were affected except for Müller cells, astroglia in the optic nerve head, epithelium of the pars plana, and the pigment cells of the choroid. The possibility is raised of a nonischemic pressure-induced mechanism for destruction of disc astrocytes in human chronic glaucoma.
A chronic elevation of the episcleral venous pressure may occur after venous obstructive disease or arteriovenous fistulas in the orbit, head, neck, or mediastinum. Idiopathic and familial occurrences of elevated episcleral venous pressure have been reported. Association with an increased episcleral venous pressure is a rise in intraocular pressure which, if of sufficient magnitude and duration, may cause cupping of the optic nerve and visual field loss. A case of glaucoma with visual field loss secondary to elevated episcleral venous pressure is presented. Recognition of the etiology of such cases is important, since the management of these patients differs from that of patients having primary open-angle glaucoma.
Retinal functionality during short-term intraocular pressure (IOP) elevation and simultaneous systemic blood pressure (BP) variations was evaluated in the cat by recording the electroretinogram in response to both homogenous flickering light (FERG) and contrast reversing gratings (PERG). The mean arterial blood pressure (BPm) was pharmacologically adjusted to different levels and a large range of IOP values was tested. Results indicate that both FERG and PERG responses are impaired when the eye perfusion pressure (PP = BPm - IOP) is reduced and they disappear at a critical PP value of about 20 mm Hg, irrespective of the absolute value of the IOP. In addition, when the critical perfusion pressure is maintained for periods longer than 5 min, the recovery of the PERG response, when present, is always delayed compared to the full recovery of the FERG response. These findings support the hypothesis that vascular factors, ie, the impairment of the retinal blood supply, may be responsible for the disappearance of the retinal electrical activity during short-term IOP elevation. Furthermore, the retinal ganglion cells, presumably the main source of the PERG response, appear less likely to recover from the acute ischemic episode.
Although previous studies have suggested that aging results in an increase in vascular stiffness, diseases that increase in prevalence with advanced age may have confounded the results of some of this past research. The purpose of this investigation was to determine whether aging per se results in reduced arterial compliance by using animals that are resistant to atherosclerosis and do not develop hypertension or hyperlipidemias with advanced age. We evaluated systemic and regional (femoral) arterial compliance in older (110 +/- 8 months old) and in younger (27 +/- 2 months old) female beagle dogs by using a computer-based assessment of the diastolic decay of arterial pressure waveforms and a modified Windkessel model of the circulation. Although systemic arterial pressure was very similar in both age groups, cardiac output was 29% lower (p = 0.03) and systemic vascular resistance was 24% higher (p = 0.02) in the older dogs. Moreover, there was an age-related reduction in systemic arterial compliance, derived both from the exponential decay in the arterial pulse (C1) (p = 0.05) and that derived from the oscillatory component of the diastolic pulse wave (C2) (p = 0.04). By contrast, although femoral vascular resistance was 25% higher in the older dogs (p = 0.04), regional (femoral) vascular compliance measured after femoral arterial occlusion was also 25% reduced but was not significantly changed with age (p = 0.14). These results demonstrate that systemic arterial compliance is reduced with age in dogs, extending this finding to animals without age-related diseases that frequently occur in older human beings. Regional compliance, evaluated in the isolated femoral vascular bed, also tends to be reduced with age, but variability in this parameter in dogs reduces the significance of this finding.
In this twofold study, part 1 aimed to determine whether the playing of high resistance wind instruments elevates intraocular pressure (IOP) and if so, to investigate the mechanism of IOP elevation and whether its magnitude differs while playing high resistance versus low resistance instruments. The purpose of part 2 was to evaluate whether high resistance players have a greater incidence of glaucomatous changes than other musicians.
Three case reports and a cross-sectional study.
Two players of high resistance instruments and one player of high and low resistance wind instruments participated in part 1 of the study. Nine high resistance wind players, 12 low resistance wind players, and 24 nonwind players were recruited among professional musicians in the Boston area to participate in part 2.
In part 1, IOP and uveal thickness changes were measured by pneumatonometry and ultrasound biomicroscopy in two participants playing their high resistance wind instruments (trumpet and oboe) and in a third participant playing both high (trumpet) and low (clarinet and saxaphone) resistance instruments. Each musician in part 2 underwent medical and musical history, measurement of IOP, Humphrey visual field testing, slit-lamp examination, gonioscopy, and dilated examination.
Intraocular pressure and uveal thickness changes, and visual field loss and optic nerve head appearance were the main parameters measured in part 1 and part 2, respectively.
In part 1, pneumatonometry showed IOP elevation dependent on the force of blowing, and ultrasound biomicroscopy revealed uveal thickening associated with IOP elevation. The magnitude of IOP elevation was dependent on the amount of expiratory resistance provided by the particular instrument. Part 2 showed that life hours of high resistance wind instrument playing had a significant relationship to abnormal visual field (P = 0.03) and corrected pattern standard deviation (CPSD) scores (P = 0.007) in univariate logistic regression and univariate linear regression, respectively. A 0.011-unit increase in CPSD for each 1000 life hours of high resistance wind playing was found.
High and low resistance wind musicians experience a transient rise in their IOP while playing their instruments as a result least in part of uveal engorgement. The magnitude of IOP increase is greater in high resistance wind players versus low resistance wind players. High resistance wind musicians had a small but significantly greater incidence of visual field loss (abnormal fields and increased CPSD scores) than other musicians, which was related to life hours of playing. The cumulative effects of long-term intermittent IOP elevation during high resistance wind instrument playing may result in glaucomatous damage, which could be misdiagnosed as normal-tension glaucoma.
To determine the electrodiagnostic and histologic response of short-term increases of intraocular pressure (IOP) on transient pattern electroretinograms (PERG) and flash electroretinograms (FERG) in the eyes of dogs.
8 healthy mixed-breed dogs.
Transient PERG and FERG waveforms were recorded from dogs (while anesthetized) as IOP was increased from baseline (7 to 19 mm Hg) to 90 mm Hg. One hundred mean PERG responses and a single FERG response were recorded at each step during 3 recording sessions. Globes of each dog were enucleated after euthanasia on posttreatment day 7 and evaluated by a pathologist.
Increases in spatial frequency resulted in decreased amplitudes of N2 (second negative PERG peak). Increases in IOP resulted in decreases in all 3 PERG waveforms and the FERG waveform. All values began to return to baseline after short-term increases in IOP on day 0, and waveforms were not significantly different on posttreatment days 3 and 7
Data suggest that short-term increases in IOP affect PERG and FERG waveforms, and PERG waveforms are more sensitive to increases in IOP Differences were not detected between treated and control eyes on histologic examination. Further studies are necessary to determine at what IOP permanent damage to ganglion and photoreceptor cells will develop and whether PERG is a reliable clinical diagnostic technique for use in dogs to reveal retinal damage that is secondary to increased IOP prior to changes in waveforms generated by FERG in dogs.
To investigate the effects of acute intraocular pressure (IOP) elevation on optic disc morphology.
Ophthalmodynamometry was used to increase the IOP of normal, healthy eyes. Confocal scanning laser ophthalmoscopy of the optic nerve head using the Heidelberg Retinal Tomograph II (Heidelberg GmbH, Heidelberg, Germany) and IOP measurements were obtained before, during, and after IOP elevation.
Sixteen eyes of 16 normal volunteers (mean age, 32.8 +/- 11.9 years) were enrolled. Rim area, rim volume, cup area, cup volume, cup-to-disc ratio, mean cup depth, maximum cup depth, mean retinal nerve fiber layer (RNFL) thickness, and RNFL cross-sectional area showed significant changes during IOP elevation (all P < .05, paired t test). All measured parameters returned to their original values after pressure resolution (all P > .2) except mean RNFL thickness (P = .03).
Transient elevation of IOP results in measurable alterations in optic nerve head topography.
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