Sherry J. Bass

Flash visual evoked potential (VEP) in amblyopia and optic nerve disease.

Amblyopia and optic atrophy are two very different causes of unilateral long-standing visual impairment. Yet, in some patients the differential diagnosis is not always manifest and standard clinical tests may fail to provide accurate information. We tested the efficacy of a nonstandard clinical test [flash visual evoked potentials (VEPs)] and quantitative ultivariate statistical techniques as aids in the assessment of this differential. Thirty-three patients were separated into four groups (normal, anisometropic amblyopia, strabismic amblyopia, and unilateral optic atrophy). Nonpatterned flash VEPs were obtained using several different temporal frequency rates. Patients with optic atrophy had significantly reduced VEPs in the affected eye at all temporal frequencies. Strabismic amblyopes, but not anisometropic amblyopes, often showed upranormal responses in the affected eye at the higher temporal frequencies. Finally, by using discriminant analysis (DA) we were able to classify correctly almost 70% of the patients, well above chance level of 25%. This DA provided very good sensitivity and specificity. We have shown that the use of flash VEPs and of multivariate statistical techniques may provide an effective way to diagnose amblyopia differentially from optic atrophy.

Optic pit, microphthalmos and orbital cyst.

An orbital cyst was discovered by ultrasonography behind the globe of the left eye in a five-year-old boy with a left esotropia. In addition, an optic pit was present in the optic nerve head of the same eye, which was microphthalmic relative to the right eye. Although orbital cyst has been reported in the literature, this case is of interest because of the presence of two congenital anomalies in the same eye - namely, optic pit and orbital cyst. These two conditions have never been previously reported as existing together in the same eye.

Optic disk evaluation and utility of high-tech devices in the assessment of glaucoma.

BACKGROUND Every clinician has at one time or another examined a patient who was misdiagnosed as having glaucoma or whose diagnosis of glaucoma was missed. Although glaucoma can exist with normal intraocular pressures, clinicians often rely on the presence of visual-field defects and the degree of optic disk cupping to direct care. However, assessment of cupping is but one small part of optic disk evaluation in glaucoma, and other features of the optic nerve head and retinal nerve fiber layer must be closely inspected to help diagnose borderline cases. In addition, glaucoma can exist without visual-field loss. High-tech devices offer an added dimension in the objective assessment of structure when subjective tests of function and/or ophthalmoscopic observations are equivocal. METHODS This article details the various parameters of optic disk and retinal nerve fiber layer evaluation and their significance in the assessment of glaucoma. In addition, the role of four high-tech devices is evaluated for their utility in the assessment and progression of glaucomatous damage. CONCLUSIONS When one attempts to classify a patient as having glaucoma, the degree of cupping and the presence or absence of visual field loss can be misleading. Prior to definitive diagnosis, a thorough evaluation of the optic disk and retinal nerve fiber layer, and appropriate use of high-tech devices, should help reduce the under-diagnosis and overdiagnosis of this disease.

Autosomal dominant pericentral retinochoroidal atrophy.

Purpose: To describe a family pedigree with a newly described hereditary retinal disease. Methods: Five family members were examined, and a fifth deceased family member was identified through review of old medical records. Results: Five individuals had annular or arcuate pericentral areas of retinal (younger members) or choroidal (older members) atrophy and spared maculae with good visual acuity and normal retinal periphery. Two of the four examined affected family members were symptomatic only for field loss; the other two were asymptomatic. No nyctalopia was reported by any affected individual. Fluorescein angiography revealed hyperfluorescence in the affected areas in the family members with retinal atrophy and hypofluorescence in affected areas in family members with choroidal atrophy. Visual field scotomas were dense and corresponded to the areas of retinal and/or choroidal atrophy. Full-field electroretinograms were normal for two family members and were reduced for one family member with the most advanced retinal and choroidal changes. The scotopic response was only mildly reduced in the fourth examined family member. Conclusions: We believe that we have identified a pedigree with a previously undescribed autosomal dominant hereditary retinal disease characterized by arcuate retinal and retinochoroidal atrophy and normal visual acuity.

Visual acuity recovery in a case of idiopathic retinal vasculitis aneurysms and neuroretinitis.

Purpose. To describe the visual recovery after intravitreal injections of the antivascular endothelial growth factor, bevacizumab, in a case of vaso obliteration from idiopathic retinal vasculitis, aneurysm, and neuroretinitis (IRVAN). The name IRVAN was given to the condition to highlight the key findings present in the disease. IRVAN is a severe, sight threatening condition that can lead to peripheral capillary non-perfusion and vision loss from the ischemic sequelae of vascular occlusion. Panretinal photocoagulation (PRP) is the current standard of care for IRVAN but visual outcome is poor if PRP is initiated after neovascularization develops. Intravitreal bevacizumab has success at treating neovascularization from other ischemic retinopathies and inflammatory retinal conditions that have similar characteristics to IRVAN. Case Report. This case report describes a patient with decreased vision in the OS. The patient presented with best-corrected visual acuity of 20/20 in the OD and count fingers at 4 ft in the OS. Evaluation revealed findings consistent with an advanced stage of IRVAN. Anterior and posterior neovascularization had developed from extensive capillary non-perfusion in both retinas. A dense vitreous hemorrhage blocked vision OS. Bilateral intravitreal injections of bevacizumab and extensive PRP were given in the area of retinal ischemia for treatment. After 4 months, the patients vision had improved from count fingers in the OS to 20/40. Conclusions. IRVAN has favorable outcomes when treated with a combination of PRP and intravitreal injections of antivascular endothelial growth factor. This case demonstrates the effectiveness of this combination treatment in a case of IRVAN with both posterior and anterior neovascularization.

A Thr17Met mutation is associated with an unusual retinochoroidopathy in an autosomal dominant pedigree.

Purpose: To report the results of molecular genetic analysis for a proband with unusual regionalized retinochoroidopathy in an autosomal dominant pedigree originally reported as a previously undescribed condition. Methods: Genomic DNA was obtained from the proband’s leukocytes and was analyzed by Carver Laboratories at the University of Iowa (Iowa City) specifically to look for variants in genes associated with autosomal dominant retinitis pigmentosa. Results: A probable high-penetrance disease-causing sequence variation in the rhodopsin gene, a heterozygous cytosine-to-thymine ACG>ATG nucleotide substitution resulting in a threonine to methionine (Thr17Met) amino acid change, was detected. This variant is associated with autosomal dominant retinitis pigmentosa. Conclusion: Findings of molecular genetics analysis of this unusual regionalized retinochoroidopathy support the diagnosis of a mild, delimited form of autosomal dominant retinitis pigmentosa.

OCT in a Myelinated Retinal Nerve Fiber Syndrome with Reduced Vision.

Purpose The prognosis of success with vision therapy in refractive “amblyopia” associated with the syndrome of myelinated nerve fibers (MRNF), optic disc hypoplasia, and myopia is reported to be poorer than that of anisomyopic amblyopia without these features. The reason for the poorer prognosis has not been well understood. The purpose of this study was to perform spectral domain (SD) ocular coherence tomography (OCT) to determine if there is a structural etiology that may explain the poorer prognosis. Case Reports Case 1 was a 12-year-old male patient with anisometropic “amblyopia” in the right eye, MRNF denser superiorly, a hypoplastic disc, and a myopic fundus with a flat intact macula. The OCT demonstrated an attenuated photoreceptor integrity line (PIL) in the macula. Case 2 was a 10-year-old male patient with a constant left esotropia, MRNF denser superiorly, a hypoplastic disc, and a myopic fundus with a flat intact macula. The OCT demonstrated an absent PIL. Case 3 was a 58-year-old female patient with a history of diabetic retinopathy OU, long-standing reduced vision in the right eye, MRNF denser superiorly, optic nerve hypoplasia, and a myopic fundus with an intact macula. The OCT demonstrated an absent PIL in the macula. Conclusions This case series identifies three patients with the syndrome of MRNF, optic nerve hypoplasia, and anisomyopia in one eye with reduced vision and reports OCT findings using SD-OCT systems. All three patients demonstrated an absence or attenuation of the photoreceptor integrity line (PIL) in the macula in the affected eye. To our knowledge, there is no known association between this syndrome and abnormality of the PIL reported in the literature. Patients with this syndrome may have a guarded prognosis in the success of vision therapy.