An 11-year-old girl presented with diplopia and papilledema. MRI and a lumbar puncture enabled a diagnosis of idiopathic intracranial hypertension. Repeated lumbar punctures and treatment with acetazolamide temporarily normalized extremely high intracranial pressure. Papilledema, abducens palsy, and visual field abnormality also resolved. However, prolonged intracranial hypertension may cause permanent visual loss and visual field defects. Careful monitoring and management of such things as visual acuity, visual field, cerebrospinal fluid, optic disk features, and MRI findings are important. Optical coherence tomography is an easy, safe, and quantitative method compared with repeated lumbar punctures, and we suggest its measurements of retinal nerve-fiber layer around the optic disk are useful for monitoring young children with idiopathic intracranial hypertension.
We investigated the clinical features and clinical course of three cases of Leber's hereditary optic neuropathy (LHON) that were associated with non-11778 mitochondrial (mt) DNA point mutations. A 14484 mutation was found in a 40-year-old male and a 49-year-old male, with the latter case diagnosed as having normal tension glaucoma. In the third case, the rare mtDNA 9804 mutation was observed in a 12-year-old female. While there was no family history of LHON in any of the patients, certain environmental factors were detected in the two cases with the 14484 mutation. However, unlike what is usually seen in patients with the 11778 mutation, these three cases were determined to have relatively better visual outcomes.
A 16-year-old girl had been complaining of visual disturbances of an unknown cause for ten years. She was diagnosed as having a learning disorder (LD) and attention deficit hyperactivity disorder (ADHD). Neuroophthalmological examinations, including electrooculogram, revealed impaired upward smooth pursuit and upward gaze-evoked blepharoclonus. Although MRI did not reveal any focal lesions, it was believed that frontal eye field immaturity was responsible for the abnormal eye movement. Her quality of life improved with the use prism glass orthoptic and orthopsychiatric guidance.
Upon absorption of light impulse by photoreceptor cells, 1st retinal neuron, light signal is converted into an electrical signal by a series of biochemical cascade reactions described in chapter 1. Then this simply evoked signal is further processed by the 2nd (bipolar cell) and 3 rd retinal neurons (ganglion cell) to create more complicated signaling during the retinal neuronal circuit. Signal from the photoreceptor cells is transferred by glutamate as a neurotransmitter to bipolar cells. Functionally bipolar cell is classified into On- or Off-type which are excited or inhibited in response to light exposure. During the direct connection between bipolar cells and retinal ganglion cells, indirect connection of bipolar cells to the ganglion cells that are also present via the amacrine cells. Within this neuronal connection, the inhibitory neurotransmitters γ-amino butyric acid (GABA) and glycine, are act as function in a lots of different roles.
Studies in bio-medical effects caused by viewing 3D images are reviewed in relation to the autonomic nervous system and related ocular functions. A short historical view of bio-medical risks on 2D images is also presented. Recent efforts in the International Organization for Standardization (ISO) are also introduced along with the presentation of a new international guideline dealing with "image safety" that is designed to prevent possible biomedical risks.
It is recognized that stress, discomfort or motion sickness caused by viewing video images such as 3D and immersive video can affect the autonomic nervous system. Therefore, in order to evaluate visual images and the associated environment, many researchers have adopted physiological indices obtained from circulatory variables. However, there are usually problems encountered when using these indices, such as large individual differences and a low reproducibility. In the current study, we review the methods that use circulatory indices to evaluate the effect of visual stimulations. Furthermore, a new circulatory regulation system approach that can be used to evaluate the effect of visual stimulation is also introduced.
Based on a visual response viewpoint, we investigated the behavior of the vital reaction that occurs when viewing three-dimensional (3D) moving images. The study used near-infrared spectroscopy (NIRS) to measure accommodation and the amplitude of motor fusion and brain function. Similar to the altered reality that is seen when gazing at 3D images, there are also changes in the accommodative response. When viewing 3D movies, a contraction of the pupil diameter is noted, and when there is an exophoria of 10Δ or greater, there is also a decrease in the amplitude of the motor fusion. In addition, gazing at 3D images causes an increase in the cerebral blood volume, a change that is not seen when viewing 2D images. Current findings suggest that the safety guidelines for viewing 3D images need to be examined from the standpoint of the visual response.
Stereoscopic 3D imaging systems are now in practical use, which means that content creators and viewers need to be aware of the undesirable biomedical effects that are associated with these systems when changes are made in the sound developmental progress. In the present paper, we present factors and measurements on the unnaturalness of the images, viewing discomfort, and visual fatigue that results from viewing these stereoscopic images. These factors can be separated into two categories, the in-principle and the non-principle factors. In the non-principle category, these factors are related to differences in the characteristics of the left and right imaging equipment. As such, these factors can be eliminated, if so desired. The in-principle category factors are related to the horizontal binocular parallax, for which the degree needs to be carefully controlled. Although development continues to progress, there are significant issues that still need to be closely examined, and which include, the long-term undesirable biomedical effects, the potential effects on developing children, and the development of robust indices for visual fatigue.
To pursue a slowly moving target in 3-dimensional (3D) space, coordination of smooth pursuit eye movements (frontal-pursuit) and pursuit-in-depth (vergence-pursuit) is required. Previous study has shown that 3D-pursuit signals are generated in the frontal eye fields. Because these two eye movement signals are represented in different areas in the brainstem, we examined what role the cerebellar dorsal vermis plays in the processing of 3D- pursuit signals. We recorded simple spike activity of Purkinje (P-) cells from 3 Japanese monkeys. Of a total of 100 P-cells which responded during pursuit eye movements in 3D space, 41 P-cells responded both during vergence-pursuit and frontal-pursuit, thus carrying 3D-pursuit signals. 43 P-cells responded only during vergence-pursuit, and 16 P-cells responded only during frontal-pursuit. These results indicate that the majority of vermal pursuit P-cells (84%) responded to vergence eye movements. Most vergence-related vermal P-cells discharged during convergence eye movements with the velocity and position sensitivities, and they discharged before the onset of vergence eye movements. Chemical inactivation of the vermal recording sites impaired the initial phase of convergence eye movements. Our results indicate that cerebellar dorsal vermis is involved in the execution of con-vergence eye movements.
Binocular vision may not be directly related to the performance of an athlete, and the relationship between depth perception and highly skilled surgery using a surgical microscope is complicated. Regarding 3D display devices that are used in clinics, those that require various 3D displays are used for treatment, and the need for them is high. Moreover, in the advancement of surgery using 3D displays, the development of integral and holographic 3D displays has progressed very rapidly. Since backward compatibility is not necessary for medical devices for special uses, it is possible for the newest 3D displays to be used efficiently in the near future.
We report on a 7-year-old boy who was diagnosed with multiple sclerosis (MS) associated with bilateral abducens nerve palsy, bilateral horizontal gaze palsy and slow saccades during infraversion. T 2-weighted magnetic resonance imaging revealed a high signal lesion that was located in the paramedian dorsal pontine tegmentum involving the abducens nucleus, the medial longitudinal fasciculus (MLF) and a part of the paramedian pontine reticular formation (PPRF) bilaterally. After steroid pulse therapy was administered, esotropia and bilateral horizontal gaze palsy almost disappeared over the following 6 months. However there was no distinct recovery of the slow saccades of the infraversion. Although MRIs including those with Gd-DTPA enhancement did not detect any lesion at the midbrain, bilateral lesions involving fibers from the rostral interstitial nucleus of MLF (riMLF) and/or the interstitial nucleus of Cajal (INC) as well as PPRF seem to be responsible for the slow saccades of the infraversion.
A 21-year-old woman with a history of migraine presented with acute progressive horizontal diplopia with headache and was subsequently diagnosed with left abducens nerve paresis. To evaluate her lesion, MRI of the brainstem was performed using the Fast Imaging Employing Steady-state Acquisitions (FIESTA) technique. Results disclosed that the left anterior inferior cerebellar artery (AICA) holding the left abducens nerve at the root exit zone of the nerve. The current study suggests that neuropeptides, which are released from the trigeminal nerve at the onset of a migraine, may induce a sterile inflammatory vascular response (trigeminovascular epiphenomenon) at the root exit of the abducens nerve leading to compression by the vertebrobasilar artery. Thus, ophthalmoplegic migraine may be one of the causes of painful abducens nerve palsy.
We performed magnetic resonance imaging in a 15-year-old woman with left Duane's retraction, type 1. We used a true fast imaging with steady-state precession technique to obtain high-resolution images through the abducens nerve in the subarachnoid segment. Scans were obtained in the axial plane from the medulla to the midbrain and the images were reconstructed along the plane of the abducens nerve. The images showed both sides of the III and V nerves and the VII-VIII nerve complexes and demonstrated the absence of the left abducens nerve. Our study provides evidence that a new magnetic resonance imaging technique can be used to verify the absence of the abducens nerve in Duane's retraction syndrome subjects.
Here, I present a case where abducens palsy developed after renal cancer treatment, and describe a rare side effect that was caused by interferon (IFN) therapy. A 65-year-old man underwent surgery for renal cell carcinoma 5 years previous. Subsequently, the patient developed right pulmonary metastasis 2 years later and since that time has been managed with IFNa therapy for recurrence. After 4 years of IFN therapy, this conventional IFN treatment was changed to a longer-acting IFN, i.e, pegylated IFN (PEG-IFN) for better curative effect. On the day after starting the PEG-IFN therapy, he developed diplopia, and was diagnosed as having right abducens palsy. A further examination revealed that he did not have diabetes mellitus, hypertension, or inflammatory disease. Magnetic resonance imaging (MRI) of the head indicated there was no evidence of metastasis or intracranial hypertension, although he did exhibit enhancement of the right abducens nerve. At one month after the onset of the diplopia, he developed painful swelling of the right parotid gland, dry eye and dry mouth sensations. Laboratory data resulted in a diagnosis of primary Sjogren's syndrome. Considering the poor prognosis for the carcinoma and the lack of any alternative treatments, he was returned to conventional IFN therapy. His diplopia gradually improved and resolved within 5 months. IFNs have complex immunomodulating effects and can frequently induce or exacerbate autoimmune disease. In the current case, IFN activated the patient's immune system and induced acute inflammation in the abducens nerve, which caused the enhancement of the abducens nerve in MRI and the ensuing abducens palsy. When administering IFN therapy, close attention needs be paid to the potential development of autoimmune disease and if it does occur, cessation of IFN or a change in the type of IFN needs to be considered.
A 69-year-old woman suffered from right complete oculomotor nerve paresis after an operation for cerebral aneurysm at IC-PC. At seven months after onset, there was no oculomotor nerve paresis recovery, and we observed signs of aberrant regeneration (pseudo-Graefe sign, inverse Duane's retraction syndrome, and gaze-pupil dyskinesis). The patient experienced downgaze double vision resulting in gait disturbance due to limitations in her downward eye movement and pseudo-Graefe sign. We designed new eyeglasses for the patient that included a semi-transparent lens for her right eye. When using her new glasses, she was able to walk much better because the vision from her affected eye was cut off. However, there was little appearance of disability in this patient, as both of her eyes could be seen through the lenses. In cases of ophthalmoplegia where eye muscle operations are either too difficult or too risky to perform, eyeglasses using a semi-transparent lens can provide an effective method for double vision removal without any inherent cosmetic problems.
Pupillary constriction, accommodation and vergence play an extremely important role in perception of three-dimensional space, such as the sense of depth and binocular vision, and in control of visual alignment, such as convergence. Visual information (e.g., disparity, blur, and size) converges in higher brain function areas. The signal for executing motions is efficiently formed in the frontal lobe and brainstem, resulting in near responses, such as convergence movement and focusing. Moreover, a parallel circuit of the vestibulo-cerebellar system plays a role in adaptive learning control, which is important for optimization of both movements and maintenance of the eye positions, to produce elaborate near responses. We consider that vulnerability or damage of the neural circuit/mechanism controlling these near responses is one of the causes of exotropia. Based on the analysis of pupillary constriction during near responses, we also demonstrate that the pathological condition of intermittent exotropia is an excessively prolonged, abnormal near response impairment. We then describe how surgery for strabismus markedly improves near response impairments induced by three-dimensional video stimuli. In this way, we describe the "etiology of exotropia" in terms of the neuro-ophthalmology/physiology of near responses, including a review of the relevant literature and examination of our own data.
We report on a patient with unilateral internuclear ophthalmoplegia (INO) with additional abnormal eye movements, suggesting impairments of the medulla oblongata and cerebellum. A 46-year-old male noticed diplopia due to skew deviation and INO. Horizontal saccades were hypermetric to the right and hypometric to the left while vertical saccades were pulled towards the right side. Furthermore, the eyes deviated to the right side during eye closure. Horizontal smooth pursuit was impaired during the tracking of targets that were moving on the left side. Additionally, insufficient gain and defects of visual suppression in the vestibulo-ocular reflex (VOR) were recognized. Usually, unilateral INO does not exhibit saccadic dysmetria, or abnormalities of the VOR. Therefore, in this case we suggest that there was impairment of not only the medial longitudinal fasciculus (MLF) but also the medulla oblongata or cerebellum.
We examined a 22-year-old woman with acute disseminated encephalomyelitis presenting with left one-and-a-half syndrome, vertical gaze palsy, left facial nerve palsy and abnormal respiratory rhythm. One-and-a-half syndrome combined with unilateral peripheral facial nerve palsy due to the pontine lesion is specifically caused by a unilateral lesion in the lower part of the dorsal tegmentum in the pons, which was detected by MRI in our patient. She recovered from her illness one year after the onset of the disease. The site of the lesion responsible for the vertical gaze palsy was the lower pons.
Poisoning is widely known to be associated with eye movement disorders. Here, we elucidates deficits in vertical eye movements in patients exposed to diphenylarsinic acid, an organoarsenic compound. Due to poisoning resulting from drinking contaminated well water, the patients in our study exhibited higher brain dysfunction, pyramidal tract signs, cerebellar ataxia, and involuntary movements during the acute phase. Although these symptoms resolved in the chronic phase, vertical eye movements, including upward gaze-evoked nystagmus and upbeat nystagmus, which are typical of the chronic phase, persisted. These important findings indicate the possibility of residual central nervous system damage. On the other hand, previous reports showed that deficits in the central nervous system are not seen in patients with inorganic arsenic poisoning, in whom peripheral nerve disorders are more common during the chronic phase. Thus, abnormalities in vertical eye movement may be useful biomarkers of lesions in the brainstem and cerebellum induced by organic arsenic poisoning.
This review is a summary of neurological diseases that are accompanied by abnormalities in eyelid opening and closure. The three major disease categories considered are: myopathies that preferentially affect the eye muscles, impaired neuromuscular impulse transmissions at the motor endplate and lesions of the somatomotor and sympathetic nerve fibers that innervate the eyelid muscles.
We investigated pupil abnormalities of the near response in children with the "Visual Display Terminal" (VDT) syndrome. Children that use VDTs might experience many of the same visual symptoms that are seen in adults. There were 378 normal junior high school students enrolled in the study and all students answered a questionnaire related to their VDT usage. A total of 213 of the students underwent basic eye examinations and measurements of their near response, which was determined by a TrilRIS C9000. Normal waveforms of the near response were analyzed as follows: 1 Pupil constriction ratio (PCR)=(initial pupil size-maximum constricted pupil size)/initial pupil size x 100), 2 Amount of convergence (AOC)=center of the pupil position at the farthest target distance-center of the pupil position at the nearest target distance, and 3 Pupil asthenia ratio (PAR)=(initial pupil size-final pupil size)/initial pupil size x 100). All of the subjects (100%) were using various VDT devices. Values for the normal AOC, PCR and PAR were 2.6±0.6 mm, 47.7±10.8% and 12.4±13.15% (mean±standard deviation), with the proportion of the number of subjects showing abnormal scores being 26.5%, 27.2% and 21.7%, respectively. Analysis by a chi-square test indicated there was no significant difference between the normal and abnormal PAR related to the VDT usage. A high prevalence of abnormalities in the AOC, PCR and PAR in children should be considered to be a serious condition. Abnormal pupillary response to near stimulation may reflect changes in the autonomic nervous system. Further research on this syndrome in children needs to be undertaken.
We report a case of abrupt unilateral enophtalmos caused by steroid therapy. A 73-year-old female suffering from symptoms of acute conjunctivitis of her left eye did not respond to either eye drop treatments or oral administration of steroids and antibiotics. Upon CT and MRI examination, images indicated the presence of an inflammatory lesion in the left orbit leading to a diagnosis of idiopathic orbital inflammation. Her symptoms gradually worsened and mild exophthalmos appeared. In order to administer steroids intravenously, she was hospitalized and on the fourth day of her therapy, there was a sudden occurrence of enophthalmos accompanied by a disturbance of eye movement and a corneal epithelial defect. This type of occurrence is considered to be very rare and the pathological mechanism remains unclear. However, we assume that the antiinflammatory effect of the steroid on the orbit and the extraocular muscles could be the cause of this abrupt appearance of the enophthalmos.
Recently, there has been a remarkable increase in the number of battered children treated in medical institutions. Since the cause of death in most battered children is often head trauma, being able to make a head trauma diagnosis is of the utmost importance. While neurological and neuroradiological examinations are essential for this medical diagnosis, neuro-ophthalmological examinations are also indispensable. Retinal hemorrhages are frequently found in the "shaken baby syndrome". A relationship between retinal hemorrhages and brain damage have also been reported in these children. In some infants, the only pathognomonic markers of child abuse are the ocular findings. Therefore, the differential diagnosis for the ocular findings becomes one of the most important factors that can be used to manage these pediatric head trauma cases. However, at the present time there has been insufficient data accumulation concerning this differential diagnosis within Japan, and thus, it is important that a cooperative study involving pediatric neurosurgeons and neuro-ophthalmologists be undertaken in the future.
Purpose: We determined refraction, pupillary diameter, and eye alignments in young subjects with intermittent exotropia under tropia and phoria conditions. By utilizing PlusoptiX S04®, this made it possible to dynamically measure all three values under binocular viewing. Methods: Subjects who were able to correct their eye alignment in phoria, gazed at a fixation point 5 meters distant. Using an infrared transparent sheet, one eye was covered (tropia condition) and then uncovered (phoria condition). Subjects were instructed to maintain the gaze without diplopia or blurring. If they recognized diplopia, they were instructed to try and regain fusion. In each patient, we measured their dynamic refraction, pupillary diameter, and eye alignments. Results: Subjects were separated into a phoria-myopia group (PM) (n=6), and a non-phoria-myopia group (NPM) (n=7). The subjects in the NPM group did not exhibit any significant changes in accommodation. However, the subjects in the PM group had a notable myopic shift during the phoria conditions. When subjects were required to maintain the phoria condition, the shift increased. Pupillary diameter changes were the same in both groups, with a gradual pupil dilation during the phoria conditions, followed by a temporary constriction when the eye was uncovered. Discussion: PlusoptiX S04® made it possible to obtain dynamic measurements of refraction, pupillary diameter, and eye alignments. Myopic shifts in the PM were clearly observable during phoria conditions. Since these shifts are inconsistent with the pupillary changes, this enables identification of phoria-myopia. These findings may play an important role in the development of future orthoptics training therapies.
Understanding the mechanism of accommodation is fundamental in being able to find an appropriate treatment for presbyopia. Over the last century, one universal tenet concerning accommodation is the capsular tension theory of Helmholtz. This theory states that the zonule is constantly pulling the capsule in the non-accommodated state and relaxes in the accommodated state. However, immunohistological studies have revealed important roles for elastic connective tissues (elastin, collagen, fibrillin and adhesive). And the author brought forward the "Dynamic connective tissue theory". Zonular fibers transmit the contraction of circular ciliary muscle to the capsule, resulting in centripetal movement of subcapsular connective tissues and expansion of the inter-lenticular fiber space. Throughout ones lifespan, the capsular epithelial cells produce lens fibers. And as apoptosis or necrosis does not occur, the accumulation of these fibers will gradually form a hard lens. The cause of presbyopia is mainly due to narrowed space for soft tissues and inter-fibers in the capsular bag. To find a treatment for presbyopia, quantitative analysis of accommodative power is essential. The newly developed "near triad meter" (TriIris; Hamamatsu Photonics) is useful for this approach. Maximum accommodative power can be calculated by the induced rate of miosis corresponding to an age matched standard curve. Static accommodative power was found to be half of the dynamic power. Three types of intraocular lenses (IOL) were tested for the accommodative power and 2-3D was found on aged. In the future, presbyopia research needs to proceed in two directions with investigations into accommodative IOL and biological cell control of epithelial growth in the lens.
The lateral suprasylvian area (LS area) of the cat and the lateral intraparietal area (LIP area) of the monkey are involved in the control of accommodation and vergence. Recently, descending projections from the LS to the rostral area of the superior colliculus (SC) have been shown to convey control signals for accommodation. The rostral SC projects their axons to the areas related to the control of accommodation and vergence in the brainstem. The frontal eye field (FEF) and the cerebellum are also involved in the control of accommodation and vergence. FEF also projects to the SC. Therefore, the rostral SC could be a key structure in the control of accommodation and vergence.
The lens is an organ that is responsible for its own metabolism and continued growth throughout life. The main constituents of the lens are proteins, which include α, β, γ-crystallins. The ratio of insoluble proteins increases during aging and these insoluble proteins are composed of insoluble crystallins, cytoskeletal proteins and membrane proteins. The functions of cytoskeletal proteins have been previously reported and include the stabilization of cell shape, importance in accommodation, and establishment of a relationship between the membrane and cytoskeletal proteins. Glutathione (GSH) levels are low in the nucleus of the lens as compared to the cortex, thus resulting in an increased ability for oxidization to occur. However, the nucleus prevents oxidation by changing to a yellow color and acting as a filter with reduced transmission. During aging and accommodation, the thickness of the lens increases and the depth of the anterior chamber decreases. Upon examination of a transparent 40-year-old lens, one already finds that the structure is abnormal. Presbyopia is strongly related with sclerosis of the lens during aging.
While various previous studies have examined near reflex, there is no instrument that simultaneously records the pupil diameter and convergence during accommodative stimulation. In an attempt to objectively measure near reflex, we have recently developed an infrared-pupillograph with an eye movement recorder. This device is not only useful in basic research but also during ordinary clinical examinations.
The accommodation/miosis/convergence functions of the near reflex are coordinated in the midbrain integration center. This study used TriIRIS® to examine the dynamics of pupils and horizontal eye movements during three trials of accommodative near/far stimuli. (1) Pupillary constriction rate (CR) corresponded well with the loaded diopter (D). (2) Normal response curve was stable for each near-far movement and the CR was about 6%/D. (3) Binocular visual ability was found to be essential for this procedure. Exotropic eye movement was parallel with monovision and the CR was almost half of the normal response. The exophoric CR for the binocular trial was normal, but reduced to half in the monocular trial. (4) Abnormal curves revealed specific patterns with regard to their accommodative insufficiencies including: a) spasm with declining mydriatic amplitude, b) weakness with low amplitude, c) a decline when both miotic and mydriatic amplitudes receded and d) paralysis when pupillary response faded away despite normal eye movement. (5) Frequencies of blinking were also found to be an important artifact in the detection of dryness and autonomie insufficiency. This novel method may objectively and precisely reveal the quantitative power and qualitative pattern of accommodative dynamics. This analytical technique may clarify the functional nature of asthenopia and provide therapeutic information.
We present a patient with ischemic optic neuropathy associated with antiphospholipid syndrome whose vision improved after hemodialysis. A 49-year-old man presented with a complaint of blurred vision. He had renal dysfunction and a diagnosis of antiphospholipid syndrome was made based on the evidence of antiphospholipid antibody in the blood. Our examination showed optic atrophy and sclerosis of the retinal arteries. His corrected visual acuity was (0.5) OD and (0.8) OS. Goldmann perimetry revealed bilateral relative central scotoma. Five years later optic atrophy was more apparent. The visual fields were more depressed and his visual acuity was (0.02) in each eye and hemodialysis was begun. His visual acuity began to improve and within 6 months his visual acuity was (0.08) OD and (0.3) OS. Our results indicate that hemodialysis may be an effective treatment for progressive optic atrophy associated with antiphospholipid syndrome and renal failure.
Essential blepharospasm is a kind of cranial dystonia, which is characterized by spontaneous and unconscious spasm of the muscles in the upper half of the face. Meige syndrome is an orofacial-cervical dyskinesia with blepharospasms as the cardinal sign. Apraxia of lid opening is a condition where there is an inability to open the lid and sometimes it accompanies essential blepharospasm. Ocular diseases, neurological diseases, and psychological diseases may promote the onset of the blepharospasm, and may also affect the course of the disease. Although the exact neuro-pharmacological basis of blepharospasm has not been determined, the presence of an abnormality in the inhibitory GABAergic system in the central nervous system is suspected. Neuro-pharmacological agents, such as etizolam, may induce this condition. Our PET studies have revealed high glucose metabolism in the thalamus, basal ganglia, cingulate gyrus, and cerebellum of patients with both essential and drug-induced blepharospasm. Low glucose metabolism was present in the visual cortex and cuneus in these patients. The density of benzodiazepine-GABAA receptors was decreased in the operculum. Glucose metabolism in patients with apraxia of lid opening was especially low in the medial surface of the frontal cortex. We suspect that the cause of blepharospasm is related to these changes.
The Acetylcholine receptor (AChR) of muscles has two types of isoforms, fetal and adult types. Each AChR subtype consists of α, β, δ and γ or ε-subunits, with fetal AChR characteristically having the γ and adults has ε-subunit. The samples studied were from normal human extraocular muscles (EOM), other striated skeletal muscles and the thymus of patients with myasthenia gravis. Using the RT-PCR method we investigated the expressions of mRNA of AChR subunits in these fresh tissues to further clarify the characteristics of EOM. All samples expressed the γ-subunits, but some did not express the ε-subunits. These results indicate that fetal AChR can be present not only in the EOM, but also in all kinds of skeletal muscles and thymus.
A 74-year-old woman experienced repeated episodes of positional vertigo, during which she exhibited horizontal, conjugate, and high frequency eye oscillation. This was initially considered to be ocular flutter upon hospitalization. Neurological findings, laboratory data, and brain MRI imaging didn't indicate the involvement of the central nervous system, thus, peripheral vestibular dysfunction was suspected. Electronystagmography (ENG) showed a horizontal direction-changing geotropic positional nystagmus, indicating that the vertigo was of the horizontal semicircular canal type BPPV. Moreover, during the multiple attacks of the recurrent vertigo she was experiencing, the patient herself indicated that the blurring of the vision could be provoked in part by her willed effort. The ENG recording was that of typical voluntary nystagmus. Voluntary nystagmus is generally identified during childhood. However, this case was unusual with regard to the late acquisition of this particular nystagmus, which followed the episodes of horizontal semicircular canal BPPV.
Functional magnetic resonance imaging (fMRI) during visual stimulation can detect regional cerebral blood flow changes that reflect neural activity in the lateral geniculate nucleus and primary visual cortex, which are major relay points in the human afferent visual system. FMRI has been used in the clinical evaluation of visual disorders such as homonymous hemianopia and unilateral eye diseases (optic neuritis, amblyopia, and so on). Future development in the data acquisition and data analysis may facilitate the use of fMRI for the management of patients with visual deficits and understanding of the visual disorders.
Visual information is of various types and includes form, color and motion. There have been no studies that have only measured just the responses to visual stimuli of luminance change without form information in area V1. To achieve a spatially uniform brightness change that excluded color and form, such as Ganzfeld stimuli, subjects wore semi-transparent covers on their eyes. Through the use of fMRI, we were able to measure the V1 responses while subjects viewed instantaneous or gradual brightness changes. Our results indicated that responses to temporal contrast changes of brightness without spatial contrast in area V1 do exist. These results must have been caused by responses in area V1 that were a combination of the transient responses to the instantaneous brightness change and the sustained responses to the value of luminance.
Patients with severe macular diseases need eccentric viewing to see a target because of central scotoma. However, eccentric fixation is often difficult and visual acuity measurements are unstable in these patients. We developed a multiple letter acuity chart (MLAC) in which many Landolt rings ("C") of the same size and direction were printed. This chart projects the "C" outside of the lesion regardless of the status of the patient's fixation, and it allows us to measure eccentric acuity in patients with central scotoma. Macular hole patients revealed better acuity with a MLAC than with a standard acuity chart preoperatively, but the difference between acuities as measured by the 2 charts was minimized postoperatively. This suggests that standard charts underestimate preoperative acuity and then overestimate improvements of acuity after surgery. Similar results were observed in age related maculopathy. Our study suggests that we must be very careful in determining acuity patients with in macular diseases.
Purpose: To describe the clinical characteristics and visual acuity outcome in methanol toxic optic neuropathy patients after treatment with high-dose intravenous methylprednisolone.
Method: This is a descriptive retrospective study. Data were gathered from the medical records of 244 patients (488 eyes) diagnosed with methanol toxic optic neuropathy over a 5 year period (January 2010 until December 2014). They were treated with high-dose intravenous methylprednisolone 1 g/day followed by oral methylprednisolone 1 mg/kg which was tapered off. The sex, age, onset of blurred vision, time interval between alcohol ingestion and the treatment, funduscopic examination and visual acuity during the initial assessment, on the third day and at the one week, two week and one month follow-up visits were obtained and analyzed.
Results: There were 244 patients included in our study. Two-hundred-twenty six (92.6%) were male. One-hundred-six (43.5%) were 26-35 years of age. One-hundred-sixty-nine (68.3%) had onset of visual loss 24 hours after alcohol exposure. One-hundred-eighty-seven (64.5%) had an interval that was 2 days – 1 week between alcohol ingestion and steroid treatment. One-hundred- sixty-five (67.6%) had optic disc swelling seen by funduscopy. Most patients had an initial visual acuity between light perception and counting fingers at 1 meter. On the third day of intravenous methylprednisolone treatment, 288 out of 488 eyes (59%) showed improvement of visual acuity, 175 eyes (35.8%) showed no improvement and 25 eyes (5.1%) had decreased visual acuity.
Conclusion: The majority of patients were male and most cases were between the ages of 26-35 years of age. Loss of visual acuity mostly occurred after 24 hours of alcohol ingestion and the majority of cases received treatment 2 days–1 week of alcohol ingestion. Fundusopic examination showed optic disc swelling in most cases. Treatment with high-dose intravenous methylprednisolone may improve visual acuity of patients with methanol toxic optic neuropathy.
We used a new dioptric accommpdater (WOG Ltd.) with infrared videopupillography to evaluate changes in pupil size, eye movement and visual acuity of near vision before and after instillation of phenylephrine (PE), an adrenergic agent or tropicamide (TR), an anti-cholinergic agent. Thirteen healthy young volunteers were included in this study. The target was moved from 50 to 10 cm three different times at a constant velocity of 0.3D/sec. Eye movement and pupil diameter were recorded. The same procedure was performed 1 hour after the topical applications of PE or TR. The mean visual acuity for near vision was 1.0. Before instillation, convergence with pupil miosis was induced in all cases. While no major changes existed after PE, after TR instillation, the near visual acuity was reduced to 0.28 and there was a slight convergence insufficiency. Loss of accommodation with pupil dilatation that was induced by an anticholinergic agent resulted in convergence insufficiency and decreased near vision. However in young subjects if the accommodation was preserved, then near vision with convergence was also well preserved even though the pupil was dilated.
A 13-year-old boy developed sequential bilateral visual loss with inter-eye delay of 1 year. Mitochondrial DNA mutation at nucleotide position 11778 of Leber's hereditary optic neuropathy (LHON) was detected in the patient who had affected and unaffected maternal relatives. During the acute stage of visual loss in the right eye, the study of flash visual evoked potential was normal whereas pattern reversal visual evoked potential demonstrated prolonged P100 latency without any amplitude reduction which is unusual for LHON.
We report a case of unilateral acute posterior multifocal placoid pigment epitheliopathy (APMPPE) associated with anterior ischemic optic neuropathy. A 61-year-old woman was referred to our hospital with a defect of the paracentral visual field of the right eye. Fundus examination revealed multiple yellow-white placoid lesions around the macular and optic disc edema in the right eye. Fluorescence angiogram demonstrated a characteristic hypofluorescence in the early phase followed by late hyperfluorescence of the placoid lesions, suggesting a diagnosis of APMPPE. Hypofluorescence was also observed in the right optic disc on the early phase angiogram. Although her corrected visual acuities were 30/20 in both eyes, paracentral scotoma leading to the blind spot was detected in the right eye. Thus, the optic disc edema was likely caused by anterior ischemic optic neuropathy. Corticosteroid pulse therapy was initiated, and the right optic disc edema and placoid retinal lesions gradually disappeared. However, optic nerve fiber defects with a corresponding visual field defect remained. The optic nerve head and posterior choriocapillaris are supplied by the short posterior ciliary artery. We suggest vasculitis in these vasculatures might obstruct the vascular beds in the optic disc and posterior choriocapillaris, causing unilateral APMPPE associated with anterior ischemic optic neuropathy.