EOG as a monitor of desferrioxamine retinal toxicity

Iron overload caused by blood transfusion-dependent anaemia usually results in lethal cardiac toxicity unless treated by iron-chelation therapy. Chelation therapy with desferrioxamine (DFO) is well established and widely used to remove excess iron. Unfortunately, visual disorders have been recorded after DFO infusion. In this investigation, a 61-year-old Caucasian female received DFO for her autoimmune haemolytic anaemia. Prior to starting with the DFO treatment, her baseline ophthalmic screening and electro-oculogram (EOG) were completely normal. Two years later she noticed a grey scotoma in her right eye. Visual acuity in this eye was reduced from 6/5 to 6/9 and funduscopy revealed evidence of non-specific mottling of the retinal pigment epithelium of both retinae. The EOG was flat (106%) in the right eye and subnormal in the left (155%). The lower limit of our EOG Arden Ratio for normal subjects is 180%. After her DFO treatment was stopped, her right visual acuity returned to 6/5, her field tests showed progressive improvement bilaterally and the EOG went back to the normal range. While waiting for splenectomy, the patient was restarted on a lower dose of DFO and EOG measurements were carried out every two (or three) weeks to monitor for DFO toxicity. The EOG varied during this period indicating some deterioration of function in the retinal pigment epithelium. However, normalisation of the EOG values (right = 217%, left = 217%) occurred after splenectomy and cessation of DFO therapy. Her visual function was normal and her visual acuity 6/4 bilateral when she was discharged from our outpatient clinic. On reviewing her history it was apparent that the EOG was the most sensitive indicator of DFO toxicity.     

Acute endophthalmitis of 15-year old boy in the course of acute lymphoblastic leukemia. Part II--Electrophysiological examinations

PURPOSE: The aim of the study is to present objective estimation of visual function in eyes affected by leukemia. MATERIAL AND METHODS: The boy who was described in the first part of this study was examined. Visual evoked potential (VEP), full-field flash electroretinography (FERG), electrooculography (EOG), were done according to ISCEV standards. RESULTS: The function of retina was decreased proportionally to the areas of infiltration. The amplitude of VEP peaks was lowered when the involvement of the central nervous system occurred. In the eye with retinal infiltration abnormal EOG was present a few months earlier than pigment epithelium destruction was seen in ocular fundus. CONCLUSIONS: Functional deficits may be irreversible.     

Sector retinitis pigmentosa

Combined clinical, psychophysical and electrophysiological examinations of the visual function were performed in two patients affected by sector retinitis pigmentosa. Psychophysical dark adaptation measurements, the electroretinogram (ERG) and the electro-oculogram (EOG) revealed that a larger area of the neural retina and pigment epithelium were pathologically involved than revealed by ophthalmoscopy and visual field. Five years of observation showed a stationary retinal defect in one patient, while in the other a slight clinical but a marked electroretinographical deterioration was found over a period of twelve years. However, visual acuity and the visually evoked potential (VEP) remained normal. In spite of subnormal ERG amplitudes, the photopic and scotopic peak latencies were normal in both cases. In the ophthalmoscopically normal relatives of one patient slight dark adaptation impairments, as well as EOG and ERG disturbances, were detected.     

Unilateral retinitis pigmentosa with amblyopia in the fellow eye

Purpose The purpose was to report a case of unilateral retinitis pigmentosa with amblyopia in the other eye.Methods Eight years ago, a 36-year-old woman complained of peripheral visual field loss in her left eye when she covered her right eye. Complete ophthalmological examinations including fundus photography and fluorescein angiography, full-field electroretinography, dark adaptation, and microperimetry were performed.Results Best-corrected visual acuity of the patient was 0.2 with +2.5 diopters in her right eye and 0.3 with +1.5 diopters in her left eye. Fundus examination did not reveal any abnormalities in the right eye, but narrow retinal vessels, optic disc pallor, and peripheral retinal pigment clumping was found in the left eye. The full-field electroretinography was normal in the right eye, but rod response, cone response, and combined response were non-recordable, and 30-Hz response was very small in the left eye. Dark adaptation thresholds were normal in the right eye, but were dramatically elevated in the left eye. Microperimetry was normal in the right eye, but the visual field was reduced to a 2×5° central field in the left eye.Conclusion Unilateral retinitis pigmentosa with amblyopia in the other eye is a rare condition. The patient presented here had a case of unilateral retinitis pigmentosa with the other eye with ametropic amblyopia. It is necessary to perform functional and morphological ophthalmological examinations to confirm the diagnosis.     

Delayed visual maturing in infants: differential diagnosis and treatment strategy]

Results of long observations of 7 infants with delayed visual maturing, diagnosed at the age of 2-4 months by ophthalmological, electrophysiological, radiological methods and registration of electroretinogram (ERG) and visual evoked potentials (VEP), are analyzed. Delay of visual maturing is characterized by disorders of behavioral visual reactions in neonates with emmetropia, absence of ocular disease and oculomotor system, normal ERG and VEP in response to a light flash or 14-110' patterns, and absence of changes in the postgenicular tract detected by radiological examination. Diagnostic criteria of delayed visual maturing and symptoms important for differential diagnosis are defined.     

A case of localized retinal damage in thallium poisoning

Purpose: To determine the cause of visual impairment and to document the late eye disturbances in a case of thallium poisoning. Patient: A 44-year-oldwoman presented with a history of repeated attacks of complete alopecia over a period of several months, diffuse pain in both legs, transient gastrointestinal disturbances, abasia with a progressive paraparesis, paresthesia in the fingertips, and polyneuropathy. She complained of slowly progressive visual deterioration in both eyes which began about six months after the first attack of alopecia. The optic discs showed distinct signs of temporal atrophy together with a deep temporal excavation. The Goldmann perimetry revealed an absolute central scotoma. Traces of thallium were found in the urine and in the serum. The district attorney later discovered that her husband had been trying to poison her with thallium. Methods: The clinical and electrophysiological examinations included visual evoked potentials (VEP) and electroretinography (flash ERG, multifocal ERG and pattern ERG). Results: The VEP showed a reduction in amplitude and a prolonged latency indicating a conduction block. The pattern ERG was initially normal. At a follow-up examination 6 years later, a slight amplitude reduction in the pattern ERG was found. The multifocal ERG showed a diminished amplitude in the center of the retina (up to± 10° visual angle). Conclusions: The electrophysiological investigations in our patient – who had an optic atrophy – indicated a conduction block of the retinal nerve fibers (VEP) and an additional lesion at or before the retinal bipolar cells (multifocal ERG),localized in the central ± 10°. These findings suggest that thallium poisoning can lead to a combined lesion of the retinal nerve fibers and the neural retina. This revised version was published online in August 2006 with corrections to the Cover Date.     

Combined photodynamic therapy and intravitreal bevacizumab injection for the treatment of adult Coats' disease: a case report

A 68-year-old woman presented with a visual field defect in her right eye. The fundus of her right eye showed multiple telangiectatic vessels, retinal hemorrhages, and subretinal exudates in the inferior peripheral retina. Nine months later, the subretinal exudates extended to the fovea despite treatment with laser photocoagulation. Cryotherapy was not possible at the time because of the posterior location of the retinal telangiectatic vessels. She was treated with a combination of photodynamic therapy (PDT) and intravitreal bevacizumab injection: three injections were given at 2-month intervals. After this combined therapy, her right fundus revealed a significant regression of abnormal retinal vessels and subretinal exudates. A fluorescein angiography showed no leakage from the abnormal retinal vessels. At 9 months after the combined therapy, she was able to maintain a stable visual acuity and visual field. This is the first case report that demonstrates the efficacy of the combined treatment of PDT and intravitreal bevacizumab injection in Coats's disease. This combined therapy is a kind of treatment modality for adult Coats' disease in cases which cryotherapy cannot be employed and are refractory to laser photocoagulation.     

The relationship of nystagmus waveform on the VEP response in infantile nystagmus syndrome: a small case series

Purpose

The relationship between eye movements and the visual evoked potential (VEP) response was examined in two subjects with infantile nystagmus syndrome (INS). Changes in VEP amplitude were compared between periods of foveation versus periods of high-frequency nystagmus. An analysis is proposed that improves extraction of the checkerboard reversal VEP signal from subjects with INS.

Methods

INS subjects were 2 healthy children (12–13 years old) with 20/40 or better corrected acuity. Optical coherence tomography confirmed the optic nerves, retina, and fovea were within normal variation. VEPs were recorded to checkerboard reversal and to onset/offset of horizontal gratings while simultaneously recording the electrooculogram (EOG). VEP epochs underwent Fourier analysis, and epochs were examined for phase consistency with the mean. Foveation periods were compared to video-oculography recordings from a separate session.

Results

Optic nerve misrouting, such as crossed VEP asymmetry seen in albinism, or ipsilateral VEP asymmetry seen in achiasma, was not detected in either subject. By averaging only epochs in which EOG epochs showed foveation, VEP amplitude could be increased ≥59%. Averaging the VEP only on epochs with consistent phase at Oz increased VEP amplitude by ≥twofold; subsequent EOG epochs after this analysis mostly contained foveation periods or minimal EOG activity. Latency varied <14 ms across all analyses.

Conclusions

The checkerboard reversal VEP signal is dependent on foveation periods in subjects with INS despite good visual acuity. Reduction in VEP amplitude due to retinal image motion induces noise and/or lack of phase locking in the VEP epochs. Selective averaging of epochs based on phase consistency improves the extraction of a VEP signal, likely when retinal image motion is minimized.

     

Bilateral AION after the combined therapy of hepatitis C with PEG-interferon alpha2B and ribavirin

INTRODUCTION: Chronic hepatitis C-therapy is limited to the combined use of PEG-ylated interferons and ribavirin. Side effects of this therapy include retinal changes that manifest with bleeding, cotton wool spots and/or thrombosis. PATIENT: A 51-year-old man presented with a sudden decrease of visual acuity. Chronic hepatitis C was known for the duration of 6 months and treated for 3 months with a combined therapy of PEG-interferon alpha2B and ribavirin. A sudden visual loss occurred in the right eye and bilateral visual field defects were detected. Ophthalmoscopic examination revealed bilateral papilloedema. After withdrawal of PEG-interferon alpha2B and ribavirin, a standard haemodilution therapy was started without functional improvement. After papilloedema regression, a beginning secondary atrophy of the optic nerve was diagnosed bilaterally. Vision did not improve. CONCLUSION: The ocular side effects of combined hepatitis C therapy with PEG-interferon alpha2B and ribavirin range from mild retinal changes to severely impaired vision. Treatment should be carried out in co-operation with an ophthalmologist. With respect to the uncertain effectiveness of hepatitis C therapy with interferon alpha2B and ribavirin, therapy should be stopped as soon as severe ophthalmological complications occur.     

Directional motion asymmetry in infant VEPs--which direction?

Monocular viewing during early infancy reveals asymmetries in optokinetic nystagmus (OKN) and visual evoked potentials (VEPs). This study investigates the VEP asymmetry to see if it is consistent in direction with the OKN asymmetry. Steady-state VEPs were recorded from infants (5-21 weeks) viewing gratings that underwent successive displacements in the same direction, leftward or rightward. In addition, transient VEPs were recorded to the two directions of an oscillating stimulus. Both tests produced larger VEP amplitudes for nasal-to-temporal compared to temporal-to-nasal movement. Horizontal eye movements were monitored by EOG while viewing these stimuli to test whether the asymmetry was a consequence of eye movements. No difference in eye movements as a function of the stimulus was found, excluding differences in retinal slip as an explanation of the asymmetry. The stronger neural response for nasal-to-temporal displacements is opposite to the asymmetry of OKN. Oculomotor and VEP asymmetries may be related; however this relationship is not simply that the stronger neural response, indicated by the VEP, leads to a stronger optokinetic response.     

Normal retinotopic mapping in human strabismus with anomalous retinal correspondence

Burian proposed that a functional retinotopic remapping of the deviated eye on striate visual cortex may be the physiologic basis for the perceptual phenomenon of anomalous retinal correspondence (ARC) in human strabismus. This investigation searched for this type of retinotopic remapping in five esotropes and one exotrope with ARC by means of visual evoked potential (VEP) topographic mapping. Uniocular stimulation of the foveas (corresponding points) during binocular vision in a normal subject yielded identical VEP scalp topographies from each eye. Stimulation of anomalously corresponding points produced different VEP scalp topographies from each eye in the six strabismic subjects. Uniocular stimulation of the anatomic foveas of each eye (noncorresponding points) in a strabismic subject during binocular vision produced identical VEP scalp topographies. These results suggest that there is no significant functional binocular realignment of retinotopic mapping in the visual cortex of human strabismics with ARC.     

Melanoma-associated retinopathy with unknown primary site in a Japanese woman

BACKGROUND: We report the clinical features of the first case of a Japanese person with melanoma-associated retinopathy. CASE: A 44-year-old woman complained of photopsia and blurred vision in her right eye, and was treated with steroids for uveitis by an ophthalmologist. She was referred to our hospital for further examination. After one month of treatment, she still complained of photopsia in her right eye. The best corrected visual acuity in the right eye was 0.8 and these was sensitivity loss in the central visual field test. Ophthalmoscopy and fluorescein angiography showed some retinal vasculitis in the right eye. A full-field electroretinogram demonstrated a negative-type electroretinogram (ERG) waveform with attenuation of the b-wave amplitude in the right eye. A dark adaptation test revealed sensitivity loss of the rods. The lymph nodes on the right side of her neck were examined and the diagnosis was made of metastic cutaneous melanoma with unknown primary site; her visual dysfunction was diagnosed as melanoma-associated retinopathy. The retinal inflammation improved after steroid treatment, but her visual dysfunction remained. Chemotherapy and an immunotherapy regimen was begun, but 36 months later she died of metastatic melanoma in the lungs. CONCLUSIONS: A woman treated for uveitis without any prior systemic and ocular diseases was diagnosed with melanoma-associated retinopathy and metastatic melanoma in the cervical lymph nodes of unknown primary origin. The first ocular symptoms were photopsia and blurred vision, not night blindness. ERG was useful for diagnosing this rare ocular condition in an early stage.     

Alström syndrome--a case report and literature review

PURPOSE: To report a case of Alstr?m syndrome referred as bilateral macular degeneration. MATERIAL AND METHODS: A 52 years old man was diagnosed with an over 30 years history of progressive visual acuity worsening in both eyes, with the presence of night blindness and photophobia. Since childhood the right eye has been positioned in a divergent deviation. General history revealed: high grade obesity, dilated cardiomyopathy with mitral insufficiency, diabetes mellitus type 2, hepatic cirrhosis with elevated serum enzymes, systemic hypertension. Family history: one patient's brother died at the age of 2 years because of a congenital heart disease, and the second brother was diagnosed for the congenital organic heart disease. The basic ophthalmic examination was performed with additional diagnostic methods including: kinetic visual field examination, Amsler grid test, panel D-15 test, fundus photography, ERG, EOG and VEP. RESULTS: Best corrected visual acuity of both eyes was 0.1. Amsler grid and color vision tests were normal. Visual field revealed concentric contraction in both eyes. The funduscopy showed pale optic discs, atrophic maculopathy, golden appearance of peripheral and midperipheral fundus, coarser pigmentary changes with a "bone-spicule" configuration and arterioral narrowing. The red free pictures demonstrated the atrophy of internal retinal layers and the infrared pictures revealed the atrophy of the external layers of the retina in posterior pole of the fundus. The flash ERG showed reduced amplitude of photopic and scotopic b-wave. The multifocal ERG demonstrated the normal function of the central retina. EOG revealed decreased Arden ratio in both eyes; 1.68 in the right and 1.32 in the left. The pattern VEP revealed the P100 amplitude reduction by 80% and elongation of latency by 120% in the right eye and normal in the left eye. The flash VEP showed normal latency and amplitude reduction by 50% in both eyes. CONCLUSIONS: Based on the results of performed tests the diagnosis of Alstr?m syndrome was established. This rare congenital autosomal recessive condition is characterized by progressive cone-rod retinal dystrophy associated with obesity, sensorineural deafness, type 2 diabetes, congenital cardiac insufficiency secondary to dilated cardiomyopathy, systemic hypertension and kidney failure.     

Exploration of retro-chiasmatic visual pathways in human albinism

PURPOSE: Several research studies have explored the abnormal crossing of the retinogeniculate and geniculocortical optic pathways in human albinos. This prospective study has dealt with visual evoked potentials (VEPs) of human subjects to identify the percentage of albinos with asymmetric VEPs. PATIENTS AND METHODS: A series of 16 albino patients ranging in age from 6 to 37 years were examined. They had measurable visual acuity, with or without nystagmus. Diffusion of flash stimuli not allowing selective study of the two visual pathways (direct and crossed), two stimulation patterns were used for VEP recordings: monocular full open field then hemi-field stimulation to isolate the activity of each visual pathway. ANALYSIS: In the normally pigmented subject, fibers derived from the nasal half of the retina of each eye decussate at the chiasma, while temporal retinal fibers are uncrossed and project to the ipsilateral hemisphere. In albinos, the majority of temporal retinal fibers subserving the nasal field (from fixation to an eccentricity of about 20 degrees ) anomalously cross with the nasal retinal fibers. Therefore with monocular stimulation, the evoked visual response should be obtained only in the contralateral hemisphere. The asymmetry, morphology and latency for the first major positive peak and the amplitude of the VEP were examined and compared with the normal population. CONCLUSION: We managed to demonstrate the characteristic VEP asymmetry only in 3 out of the 16 patients. The results presented herein lead to question the absolute validity of VEP abnormality in diagnosis of albinism for clinical purposes.     

Acute angle-closure glaucoma from spontaneous massive hemorrhagic retinal detachment

PURPOSE: To report a case of acute angle-closure glaucoma resulting from spontaneous hemorrhagic retinal detachment. METHODS: An 81-year-old woman visited our emergency room for severe ocular pain and vision loss in her left eye. Her intraocular pressures (IOPs) were 14 mmHg in the right eye and 58 mmHg in the left eye. Her visual acuity was 0.4 in the right eye but she had no light perception in the left eye. The left anterior chamber depth was shallow and gonioscopy of the left eye showed a closed angle. In comparison, the right anterior chamber depth was normal and showed a wide, open angle. Computed tomography and ultrasonography demonstrated retinal detachment due to subretinal hemorrhage. After systemic and topical antiglaucoma medications failed to relieve her intractable severe ocular pain, she underwent enucleation. RESULTS: The ocular pathology specimen showed that a large subretinal hemorrhage caused retinal detachment and pushed displaced the lens-iris diaphragm, resulting in secondary angle-closure glaucoma. CONCLUSIONS: Prolonged anticoagulant therapy may cause hemorrhagic retinal detachment and secondary angle-closure glaucoma. If medical therapy fails to relieve pain or if there is suspicion of an intraocular tumor, enucleation should be considered as a therapeutic option.     

Magnetic Resonance Imaging Changes in a Head and Neck Cancer Patient with Wernicke Encephalopathy and Visual Loss

A woman suffering from cancer presented with headache, confusion, and blurred and double vision with an unsteady gait. Magnetic resonance imaging and lumbar puncture were normal. Subsequently her visual loss and mental status worsened: examination then revealed moderate confusion; light perception vision bilaterally; upbeat nystagmus in primary gaze with gaze evoked vertical and horizontal nystagmus; and disc swelling with retinal haemorrhages. Repeat magnetic resonance imaging showed changes in her thalami, caudate, periaqueductal gray matter, and tectum. A serum thiamine level was measured and she was treated with thiamine replacement for Wernicke encephalopathy. She had near complete recovery of vision, mentation, and eye movements. Optical coherence tomography showed swelling of the retinal nerve layer, and visually evoked potential demonstrated delayed signals consistent with optic nerve demyelination. The case is the first to demonstrate rapid onset of imaging changes having a documented normal scan nine days previously.     

Optic disc pit combining with an optic nerve cyst — A case report

Herein, we report a case presenting with the optic disc pit and optic nerve cyst coexistence. A 54-year-old female presented to our office with progressive blurred vision for up to 3 months in her left eye. Upon examination, the best corrected visual acuity in the right eye was 20/20 and in the left eye was 20/100. Fundoscopic examination revealed a black pit at the temporal margin of left optic disc without obvious macular edema. Findings were confirmed later with optical coherence tomography (OCT) examination. Further magnetic resonance imaging (MRI) disclosed a well defined 6 mm x 6mm cystic lesion located at temporal aspect of left retro-bulbar optic nerve within the optic nerve sheath. Compression of left optic nerve was prominent. Visual evoked potential (VEP) test verified dysfunction of left optic nerve. She kept following up for 6 months. Neither maculopathy nor retinal edema occurred during this period. The visual acuity maintained 20/100 in her left eye. The size and location of optic disc pit remained as well. To sum up, in a patient with visual impairment combing with optic disc pit, further imaging surveys should be considered to exclude the possible coexistence of other optic nerve abnormalities.     

Transient electro-oculogram impairment in unilateral acute idiopathic maculopathy

Unilateral acute idiopathic maculopathy (UAIM) is a rare distinct entity characterized by acute exudative maculopathy occurring in young persons. The purpose of this case study is to report transient electro-oculogram (EOG) impairment during the acute stage of UAIM. A 16-year-old healthy female with UAIM in the left eye underwent serial visual field, fluorescein angiography, indocyanine green angiography, full-field electroretinogram (ERG), and EOG. Initial visual acuity of the affected left eye was 4/200 with macular subretinal exudates. Indocyanine green angiography disclosed early phase foveal hypocyanescence persisting into late phase along with late phase foci of pinpoint hypocyanescence scattered in the macular and mid-peripheral regions. Standard full-field ERG responses performed 18 days after the onset of symptoms were normal. Standard EOG revealed a marked reduced light-peak to dark-trough amplitude ratio (Arden ratio) of 1.20 left eye (normal ≥ 1.7) and a normal ratio of 2.24 right eye. Five weeks later, the left eye improved to 20/50, and the exudative maculopathy resolved with residual irregular foveal hyperpigmentation. Repeat EOG performed 69 days after onset of symptoms showed recovery and normalization of the EOG amplitude ratio of the left eye from 1.20 to 2.54. Transient EOG impairment with a normal full-field ERG may occur during the early stage of UAIM. This finding suggests a more widespread dysfunction of the retinal pigment epithelium in at least some cases of UAIM.     

Achiasmia and unilateral optic nerve hypoplasia in an otherwise healthy infant

An 18-month-old white boy, observed by his parents at 1-2 months age to have poor visual attentiveness and nystagmus, underwent an ophthalmological evaluation. The patient also underwent unsedated 5-channel flash visual evoked potentials (VEP) and sedated electroretinogram (ERG) testing as well as magnetic resonance imaging (MRI) of the brain and orbits. The VEP in response to monocular stimulation demonstrated occipital asymmetry and was clearly suggestive of crossed asymmetry and also showed right optic nerve hypoplasia. The MRI and fundoscopic examinations supported the findings of achiasmia and probable optic nerve hypoplasia. The patient also had decreased Teller card visual acuity, nystagmus and a variable right esotropia. Neurological examination was normal. The ophthalmological and MRI findings in this 18-month-old male patient support the diagnosis of isolated non-decussating retinal-fugal fibre syndrome as well as hypoplasia of the optic nerve.     

A case of presumed radiation optic neuropathy]

A case of a 37-year-old woman with radiation optic neuropathy was reported. She had undergone subtotal removal of the right orbital tumor (adenoid cystic carcinoma) by frontal craniotomy, followed by radiation therapy (64Gy). She had been quite well until she noticed a gradual loss of vision in her right eye 18 months later. Her visual acuity was 0.2 in the right eye and 1.5 in the left eye with right relative afferent pupillary defect and dense central scotoma. Funduscopy revealed optic disc swelling with surrounding retinal edema and small hemorrhage in the right eye. Fluorescein angiography revealed a hypoperfusion area and obstruction of the small retinal vessels in the posterior pole, but this was not large enough to explain the dense central scotoma. Although prednisolone therapy gave temporary improvement, the visual function gradually deteriorated.