Faculty Bibliography

Measures of hue discrimination and M (green) and S (blue) cone pathway sensitivities were compared in a group of 24 diabetics with either early background retinopathy or no retinopathy. The Farnsworth-Munsell 100-hue test was used to measure hue discrimination, and a two-color increment threshold technique was used to measure S and M cone pathway sensitivities. The results were compared to the level of diabetic retinopathy, to the degree of macular edema, and to the duration of the disease. No significant correlation was found between the Farnsworth-Munsell 100-hue error scores and the level of retinopathy; S cone pathway sensitivity loss, however, correlated significantly with both the level of retinopathy and the degree of macular edema. Our results indicate that measurements of S cone pathway sensitivity using an increment threshold technique provide a more sensitive method than hue discrimination for detecting color vision deficits in early diabetic retinopathy

We studied three members of three successive generations of a family with autosomal dominant congenital stationary night blindness and normal fundi. Psychophysical studies on two members showed normal final cone thresholds and mildly increased rod thresholds. Full-field electroretinograms on all three members showed normal photopic b-wave amplitudes and implicit times. Under scotopic conditions, the rod response was absent, and with a bright flash stimulus, there was a normal a-wave with no b-wave. This electronegative dark-adapted electroretinogram resembled the Schubert-Bornschein type seen in congenital stationary blindness, which has been seen only in autosomal and X-linked recessive pedigrees

Clofazamine is an iminophenazine dye with antimycobacterial activity which has recently been used to treat mycobacterium avium complex infections in patients with acquired immunodeficiency syndrome. The authors present the second report of a presumed clofazamine-induced bull's-eye maculopathy and generalized retinal degeneration in a patient with AIDS. The importance of closely following patients on clofazamine, especially those with AIDS who may be particularly susceptible to developing this toxicity, is stressed

We assessed the clinical utility of objectively measured acuity using visual-evoked potentials. The technique was first standardized in normal emmetropic subjects and then applied to uncorrected myopic subjects. We found that visual-evoked potential acuity could accurately indicate Snellen acuity in emmetropia and corrected myopia; however, the two measures were highly correlated only in those uncorrected myopic subjects with visual acuities of 20/100 or better. In subjects with poorer than 20/200 uncorrected visual acuity caused by myopia, estimates of visual-evoked potential acuity could not be obtained. The correlation between these two measures of visual acuity was also lower in patients with decreased Snellen acuity attributable to retinal or ocular disease. We found that patients with unexplainable claims of decreased visual acuity could be diagnosed as having functional visual loss based on objective visual-evoked potential acuities

A variety of retinal disease lead to a decrease in the sensitivity of the S (blue) cone pathways. To determine the possible sites and mechanisms of this loss we compared the sensitivities of an S (blue/pi-1) and an M (green/pi-4) cone pathway in patients with retinal diseases that differ as to their primary locus of sensitivity loss. The sensitivities of an S and an M cone pathway were assessed in patients with retinitis pigmentosa, insulin-dependent diabetes mellitus and open-angle glaucoma using Stiles two-color increment threshold technique. A greater loss in sensitivity of an S than an M cone pathway was found for all three disease groups; however, the diabetic patients showed a more selective loss. The results suggest that multiple sites are involved and that the combined effects of metabolic abnormalities and hypoxia contribute to the selective loss

Sensitivity losses in patients with retinitis pigmentosa (RP) have been attributed to a decrease in photopigment density, to a reduction in the number of photoreceptors, and also to a change in temporal response properties of the receptors. The sensitivity losses in patients with macular degeneration have also been attributed to a loss of photoreceptors. To test these explanations for sensitivity loss we obtained electrophysiological and psychophysical temporal modulation transfer functions (MTFs) on normal subjects in response to varying stimulus luminances and retinal loci. These stimulus manipulations did not duplicate the changes observed in the temporal MTFs of patients. The temporal response properties of the receptors were tested electrophysiologically by manipulating stimulus presentation interval. The results provided evidence for sensitivity losses in RP patients being due to alterations in the temporal response properties of the receptors

A mother and son with dominant cone dystrophy manifested the retinal reflexes seen in Oguchi's disease (mother) and the carrier female of X-linked retinitis pigmentosa (son). Another patient with cone dystrophy (simplex) showed localized areas of a golden reflex in each eye. A patient with juvenile macular dystrophy exhibited a diffuse golden-orange reflex throughout the posterior pole. The latter two patients did not have the Mizuo phenomenon

A 22-year-old man had a three-year history of progressive day blindness, most notably peripherally, and denied difficulty with central vision or color vision. Visual function studies demonstrated a diffuse dysfunction of the photopic system and normal scotopic function. The central cone function, however, was essentially normal. Visual acuity was 20/20 in each eye, results on AO-HRR and Ishihara color plate testing were normal, color naming visual fields demonstrated color discrimination in the central 10 degrees, and foveal adaptation was normal