Questions related to Clinical Ophthalmology
I am transplanting a polymer (Parylene-C) coated structure in the anterior chamber of the eye and expect it to reside on the iris, however, almost all of them get adhered to the cornea and not the iris. Is there any eye-physiology-related explanation to that?
Minimum rim width has been adapted by recent OCT devices since it takes more into account variability of the entry of the RNFL axons into the optic nerve canal
In Jack Holladay's publication http://www.hicsoap.com/publications/ProperMethodforCalculating.pdf wrote, that proper method for calculating average visual acuity is arithmetic mean of it in LogMAR scale. Usually this value is not much different from the average in the decimal or Snellen scale. However, this is not the case for the standard deviation, especially if variation of visual acuity in the group is small. For example, if all persons in a group have equal VA, SD of VA is 0 in LogMAR scale. But 0 in decimal scale is 1.0 (or 20/20) that seems too high estimate for the zero variability.
As a logical extension of my previous question (www.researchgate.net/post/Is_it_permissible_to_use_standard_statistical_formulas_for_mean_and_standard_deviation_of_visual_acuity_using_LogMAR_scale)
Visual acuity can be expressed using a decimal scale, the minimum angle of resolution in minutes of the arc (MAR), a natural Snellen fraction (like 20/x) and the decimal logarithm of MAR (logMAR). Khoshnood et al. (www.ncbi.nlm.nih.gov/pubmed/21205268) reveal that proper transformation of statistical values from one scale to another is untrivial task, because of the non-linearity of the transformation of VA between scales (for example y=log(x) is non-linear function, y=1/x too etc.). So all statistical calculations are best to carried out within the same scale.
At the moment, the prevailing view is that LogMAR is only proper way of expressing (and statistical processing) of visual acuity data (for example Holladay 2004 www.jcrsjournal.org/article/S0886-3350(04)00125-7/fulltext). But I can not find a detailed justification for this choice. The reference to Fechner's law looks weak, since it works mainly to describe the relationship between objective stimulus strength and it subjective sensation, for example for brightness, but I do not know how it can be applied in the case of spatial resolution.
On the other hand, the visual acuity values in the MAR scale are linearly proportional to the instrumentally measurable size of the minimum readable letter. And in the decimal scale - the maximum distance of distinguishing a letter. Thus, all statistical parameters in these scales can be linearly converted into real measurable values. Example for decimal scale: if first person has VA = 1.0 and can recognize the letter from 6 meters, second person has VA = 0.5 and can recognize same letter from 3 meters, then a person with an average visual acuity (1 + 0.5) / 2 = 0.75 will be able to recognize this symbol from average (6 + 3) / 2 = 4.5 meters. The same (but for letter's size at certain distance) is for MAR scale. In the case of LogMAR it is not so. Since this scale is logarithmic, there is no instrumentally measurable value proportional to the visual acuity in LogMAR (exept letters count in ETDRS chart, but it can hardly be considered as a physical quantity).
With this approach, despite the prevailing viewpoint, LogMAR seems to be the weakest choice among others for presentation and processing of visual acuity data.
Especial thanks to Hans Strasburger for conception of LogMAR as a strange beast and other ideas in answer of my previous question.
It's a known believe that elderly people prefer multi dose vials as eye-drops. Could you discuss about avantages vs disavantages? Anybody knows about peer reviewed studies?
For the hypertensive retinopathy stadiation there are two main classifications:
1) The Keith-Wagener-Barker classification
2) The Mitchell-Wong classification.
There are few differences between these grading systems.
I would know which one is preferable for a clinical research.
Wilson's disease is a genetic disorder caused by excess of copper in the body, the treatment includes chelating agents such as trientine and d-penicillamine and zinc acetate (Brand name: Galzin) , I can not understand what is the role of zinc acetate in the treatment?
A 6 year old girl is complaining of visual blurring for 3 days. She says that her vision is foggy all the time.
Anamnesis is negative for any possibly related disease. Seated at 3 meter distance and for near she doesn't recognize any symbol. How could you proceed with the examination and why?
I want to use it in order to explore dry eye symptom (Foreign body sensation,Itchy eye,Burning sensation,Teary eye,Photophobia,Red eye) reporting patterns and to better understand symptomatic heterogeneity in the study population.
how many group should I do and according to what the subjects can be put in groups ?
Note : each dry eye symptom was grade as 0 (none of the times ) , 1 ( some of the times) , 2 ( half of the times ) , 3 ( most of the times ) , 4 ( all of the times )
The new IOL master 700 has smaller in vivo repeatability SD for most metrics than the Lenstar, eg. 8µ instead of 35µ for AXL, 11µ instead of 40µ for ACD and 12µ instead of 80µ for lensthickness.
However, are these smaller standard deviations of clinical importance, i.e. to what extend would they contribute to a different choice of IOL power in in 'old' formulas like e.g. SRK-T and Holladay 1, and in new formulas, like e.g. Olsen or Barrett ?
The article Association of Glaucoma-Susceptible Genes to Regional Circumpapillary Retinal Nerve Fiber Layer Thickness and Visual Field Defects Article in Investigative ophthalmology & visual science 58(5):2510 · May 2017 DOI: 10.1167/iovs.16-20797 · License: CC BY-NC-ND 4.0 by Robert Rich is not the full text as described
On the one hand, Thomas et al reported a wide series of patients with foveal hypoplasia, and they found good correlation between the grade of foveal hypoplasia and the range of visual acuity that those subjects could achieve. On the other hand, some single reports have been published of patients with high grade of foveal hypoplasia and good visual acuity, calling into the question the importance of a foveal pit in achieving good visual acuity.
What do you think about this matter?
As found in the literature The OSDI is a valid and reliable instrument for measuring dry eye disease it is assessed on a scale of 0 to 100, with higher scores representing greater disability. The overall OSDI score defined the ocular surface as normal (0-12points) or as having mild (13-22 points), moderate (23-32 points), or severe (33-100 points) disease.
I think the cutoff should be > 12 , is it correct ?
Does your hospital has any guideline for preoperative PHARMACOLOGY management of cataract or glaucoma surgery?
I am trying to collect as many opinions from all over the world
Cataract surgery in low incoming countries represents a huge economic burden. Which are the best strategies in terms of kind of surgery and which kind of phacomachine will you suggest to use.
someone has the material to recommend about it? thank you all
What could cause autologous serum eye drops to precipitate? A patient has been using the drops for years due to dry eye symtpoms. Recently, three of four production series tended to precipitate when being thawed. Cold agglutinines, cryoglobulines, bacterial contamination was ruled out by lab examinations. FVIII (as one of the factors in cryoprecipitate) was only slightly elevated to 180% (upper norm limit is 150% at our lab). Electrophoresis of serum proteins was normal...any suggestions?
Globally, the magnitude of occurrences of Pterygium is over 200 million people and the prevalence varies between 0.3 % and 37%.[i] The fact remains that ocular disorders are caused by the reflected solar radiation from the surface of the earth especially the white and shining surfaces such as snow and water. [ii]
My question is what percentage of Out Patient cases in hospital undergo surgeries?
[i] Lu P, Chen XM., Prevalence and risk factors of pterygium. Int J Ophthalmol 2009;2(1):82-85
[ii] Bergmanson JP, Soderberg PG. The Significance for Ultraviolet Radiation for Eye Diseases. A review with comments on the efficacy of UV Blocking Contact Lenses. Ophtahlmic Physiol.Opt. 1995; 15: 83-91.
I am working on Insitu ophthalmic gel containing two drugs with molecular weight about 500 and 350. I need to decide the type of cellophane membrane.
Hope you will able to help me with this question. I have conducted a research regarding refractive errors. According to my results I have a total number of 150 children with different refractive errors. Among these 150, I have 50 children with myopia, 40 with astygmastismus and 20 with hypermetropia. The rest are anisometropians. Anisometropia is not a type of refractive error. So this is like a trick question...
Would it be better if I wrote instead of 150 children (300 eyes) and then count different refractive errors in each eye separately. This way I wont have anisometropias.
Hope you can help
Iopidine (apraclonidine) was once used before as a prophylactic drug to prevent IOP spikes before and after glaucoma laser procedures but it seems now to be not in the market anymore
Green technology is becoming more relevant across the board during these economic slowdowns. What is being done to improve its usage in medical sciences ?
The mainstay of treatment for an acute attack of angle closure are oral and systemic glaucoma medications. Aside from pilocarpine what is the best glaucoma topical drop to give as an adjunct?
white eyed fracture is many times misleading because of symptoms of nausea vomiting and bradycardia and as such mimics head injury. white eyed fracture needs immediate treatment and this confusion with head injury diagnosis. currently CT scan is best to check for trap door fracture of orbit.
I wonder whether infectious agents including oncogenic viruses, bacteria and possibly parasites play any role in the genesis or might acts as a factor or co-factor in the development and prognosis of the ocular tumors
17 years old Usher patient, po azetatsolamid (growing dose, now 500 mg x2) used since 12/2013. CME is getting worse, but BCVA is still about 0.5-0.6 oa. I read that intravitreal corticosteroid gives only limited and transient response - so maybe not so good idea? Anti- VEGF?? Something else?
There are many accounts showing a superior result from using a femtosecond laser in regards to epithelial ingrowth, flap thickness etc. However, the research is usually performed using older versions of microkeratomes and research showing a clear-cut clinical improvement (visual acuity etc.) seems to be totally lacking. In my clinic, my Amadeus II microkeratome produces excellent results, with a clinical outcome matching the outcome reported from using the femtosecond lasers. Also, complications are minimal compared with an older version of Amadeus I used earlier.
I have a question about accidental leishmaniasis !
The Last day I was working on my recent experiment on a new vaccine against cutaneous leishmaniasis and unfortunately I do all of my research steps lonely ,thus , when I was injecting live stationary pathogenic leishmania major to foot pad of BALB/c mice suddenly some drops of parasites suspension Sprinkled from the syringe to my eye!
I washed my eye immediately, but I want to know that I can take ocular leishmaniasis!!
It seems impossible because the eye environment condition is not suitable for this parasite, but, I want to know your opinion.
I found many article about ocular leishmaniasis as a result of visceral leishmaniasis or cutaneous leishmaniasis like as follow:
M ModarresZadeh, K Manshai, M Shaddel…-Iranian Journal of Ophthalmology , 2007
*Simultaneous occurrence of ocular, disseminated mucocutaneous, and multivisceral involvement of leishmaniasis.
Philips CA, Kalal CR, Kumar KN, Bihari C, Sarin SK.
Case Rep Infect Dis. 2014;2014:837625. doi: 10.1155/2014/837625. Epub 2014 Feb 18.
*Leishmaniasis of the eyelid mimicking an infundibular cyst and review of the literature on ocular leishmaniasis.
Veraldi S, Bottini S, Currò N, Gianotti R.
Int J Infect Dis. 2010 Sep;14 Suppl 3:e230-2. doi: 10.1016/j.ijid.2009.07.024. Epub 2009 Dec 6. Review.
*[Ocular leishmaniasis in a cat: case report].
J Fr Ophtalmol. 2013 Apr;36(4):e67-72. doi: 10.1016/j.jfo.2012.09.006. Epub 2013 Mar 1. French.
and many other.
Thanks for your comments.
In our practice we often see gas bubbles after emulsified silicone removal. It is known that these bubbles can play vital role in changing (increasing/decreasing) IOP (intra-ocular pressure). So, what do you use for full removal of emulsified silicone from vitreous cavity?
In patients who underwent glaucoma surgery especially trab surgery , is it safe to do strabismus surgery and which is better the limbal approach or the fornix approach?
I working on automatic detection of glaucoma using 3D oct images. I need a dataset of 3D retinal SS-OCT or 3D retinal SD-OCt images. I'm looking for 20-25 images contain glaucomatous eyes, glaucoma suspect and healthy eyes.
Everyday more than 1000 cataract surgeries are done through different eye hospitals, surgical mobile camps and private clinics in Nepal. Patients fall in line and their cataracts are removed. Those who are lucky see good, those who are not are told that they had existing problem at the back of their eyes. Are we treating them ?
I invite likeminded researchers to collect resources for a most needed study- Clinical audit for cataract surgery in Nepal.
Very aggressive OMMP, treatment at this moment Mycophenolate mofetil 1 g x2 and Prednisolon 30 mg/day. Of course it ( increasing pulmonar fibrous or atelectases) might be because of MMP, but I think it´s quite rare side effect.
Please I need some help with possible differential diagnoses and/or management plan. Fundus photo of an active 47year old male African, Right eye. VA=CF, exotropia approx. 30o. Lens, cornea, vitreous are all normal. Good pupillary reaction with mild RAPD, IOP 14mmHg. History of decreased vision since childhood. No history of trauma, diabetes, HIV, or hypertension. The left eye is normal.
Is topical preparation of Chlorpheniramine maleate (CPM) only (not in combination) approved by USFDA, EMA or any other regulatory body for allergic conjunctivitis?
If yes, then how CPM is marketed, OTC or scheduled drug.
Computer vision syndrome (CVS) is a temporary condition resulting from focusing the eyes on a computer display for protracted, uninterrupted periods of time. Some symptoms of CVS include headaches, blurred vision, neck pain, redness in the eyes, fatigue, eye strain, dry eyes, irritated eyes, double vision, vertigo/dizziness, polyopia, and difficulty refocusing the eyes. These symptoms can be further aggravated by improper lighting conditions (i.e. glare or bright overhead lighting) or air moving past the eyes (e.g. overhead vents, direct air from a fan). [Source: Wikipedia]
With the increasing access to digital devices, Computer Vision Syndrome is becoming a common ailment
Nowadays ours eyes do not get adequate rest as most of the time we are either on our computer, laptop, i-pad, mobile or watching television. Eye strain caused by excessive use of computer is called Computer Vision Syndrome or digital vision syndrome. It manifests as tiredness, inability to work for long hours, blurring of vision, double vision, watering, redness, itching and pain in eyes. These symptoms will be present in 95 per cent of people who use the computer for more than three hours a day.[Source: The Hindu]
Some Excerpts from the second article:
What To Do
Posture and Exercises
Good posture and regular exercises of back and cervical muscles are a must if you use the computer for more than three to four hours a day.
The room should be well illuminated with the light source positioned in a way that light does not fall directly on your eyes or on the screen The light source should be behind the screen or on the ceiling and partially covered. anti-glare screens and spectacles can also help.
Normally we blink 10 to 12 times a minute. When we watch TV our blink rate is 5 to 6 a minute and while working on the computer it further goes down to 3 to 4 times a minute. Reduced blinking causes evaporation of tears thereby increasing the osmolarity (concentration) of the tears. The hyperosmolar tears induce inflammation and tear film instability which in turn cause increase reflex lacrimation. In other words, the dry eye caused by Computer Vision Syndrome may present not only as dry eye but may present as watering and inflamed eye.
To overcome this, it is better to have the computer screen 20 to 40 degrees below the eye level. This causes partial closure of the eyes by the lids thereby decreasing the evaporative surface.
Your comments and views are welcome. Muchas Gracias !!
My aim is a survey on what seems to be a very scarcely studied subject and points to evaluate the possibility to outline the state of the art about such matter.
This is a preliminary study related to a possible methodological research about semi-neglected subjects in medicine and biology.
I am trying to assess validity of data as regards to effect of strabismus surgery on blood supply to anterior segment of eye.
A single vial of Avastin(4ml) can be used for up to say 60 patients, how does one ensure sterility of an opened vial and for how long can it be kept without compromising efficacy.
A 10 year old boy has proptosis of the right eye.. Biopsy results reveal orbital lymphoblastic lymphoma. No brain or bone marrow involvement.
This topic was covered in this month's JAMA Ophthalmology (https://archopht.jamanetwork.com/article.aspx?articleid=1838342) and reported by Medscape.
Blindness secondary to fillers used in the face is a recognized complication; it has been debated for a few years - certainly, I raised it at a meeting in London in 2012. The paper in JAMA Ophthal refers to (off-label) use in the glabellar area, and, correctly in my opinion, attributes the complication to the anastomoses between branches of the E.C.A. and I.C.A..
Unfortunately, most doctors are oblivious to this risk, and nurses even more so. In fact, I have met, even recently, 'nurse injectors' representing manufacturing companies that had no idea about this potential problem.
My advice to colleagues/ my team is as follows (which I have cut-and-pasted from my comments on Medscape):
1) Certain areas have a higher risk: malar area (medial infraorbital zone) and inferior glabellar area;
2) There can be aberrant vessels and high pressure injecting can increase the risk;
3) Cannulae are 'probably' safer in these danger zones;
4) Hyaluronidase has no established role in addressing this problem, as once the small vessels supplying the retina are occluded then the outcome is rapidly poor. Plus, from a logistical point of view, the hyaluronidase would need to be injected into the common carotid or internal carotid given that the aim is to get the enzyme to the retinal arteries a.s.a.p., and this has it's own risks;
5) Safety should trump aesthetics: I do not inject in the aforementioned danger zones. Many do, and to be honest, the risk of this adverse outcome is minute - but should it happen, it is 100% critical.
If a filler is required in the medial nasojugal area, my feeling is that it should be injected as close to the surface as possible, i.e. very superficially. Of course, the risk of the Tyndall effect is higher that way, but this could be mitigated against by the use of a monophasic filler (at least partly, and at least in theory!).
F.w.i.w., I have met a doctor and the business partner of another doctor who've caused this complication - and who have had the integrity/ strength to talk about their experiences/ learnings - and both have categorically now stopped injected anywhere within a large circumference around each eye.
I'd appreciate the thoughts of clinicians who are experienced in this field.
I am searching the data about the eyeball volume or size of young Dutch Rabbit (10~20 weeks age) for the research of ophthalmic drug.
A 42 y/o lady who candidates for PRK for myopia has history of CSCR which treated with laser photocoagulation 5 years ago. BCVA of both eyes are 9/10 and 10/10 with mild metamorphopsia.
Firm eye padding is frequently recommended as the initial management for moderate hypotony and shallow anterior chamber in the first few days post trabeculectomy. This might result from excessive filtration or a small leak.
Just wondering if there is any evidence out there in support of this, especially the bio mechanics of it. Putting pressure on a hypotonous eye might lead to some increase in the IOP, thereby forcing aqueous out and aggravating the shallow AC.
Would very much appreciate other views on this.
The standard textbooks define wet AMD as a neovascular disease. The poor response of wet AMD towards macugen therapy (anti-VEGF against VEGF A 165, a selective antivascular form of VEGF) arises the question whether wet AMD is predominantely a neovascular disease or more than that an exsudative disease. What do you think?
Meridional (or astigmatic) accommodation is defined as a non-spherical change in accommodation. Although prior evidenced-based findings supported the presence of meridional accommodation in human subjects, the underlying mechanism is still unclear.
Recently Ahn et al. (Cornea 2013; 32:971-975) published promising results on the photocoagulation (514 nm) of pinguecula. Has anybody else experience with this method?
At present it is an explosion of intravitreal injections of different antiVEGF in age-related macular degeneration, retinal vein occlusions, diabetic macular edema.
The medical treatment of glaucoma has undergone significant development in recent years. Research in this field is focused on improving pre-existing drugs and on the development of new molecules.There is also intense research activity in the search for new therapeutic groups for glaucoma treatment
Atraumatic extraction was done of right first maxillary molar with buccal infiltration and greater palatine nerve block (lignocaine 2%with adrenaline 1:80,000). The patient complains of blurred vision and pain in the lacrimal gland area of their right side. Pupil reflexes are normal, as is the healing of the socket.
Neuroprotection is a contemporary approach used in the treatment of glaucoma, retinitis pigmentosa, diabetic retinopathy.
I have one big problem with my research. I have one categorical binary dependent variable and three independent (scales) variables and I want to know which of them has the most powerful interaction that DV. I have performed the UNIANOVA on SPSS v.21, but there is something I don't see right or I don't know the right interpretation of the analysis. I know that the question is not complete but, if anyone can help me with some text about the interpretation on the UNIANOVA Analysis?
Glaucoma is a disease marked by the progressive death of RGCs and often accompanied by increases in IOP and abnormalities involving the ciliary system. But what is the anatomical connection between the two bodies?