PEG-LEG ARTERIOLES: AN ADAPTATION TO CHRONIC RETINAL HYPOPERFUSION.

PURPOSE: To describe a heretofore unreported retinal vascular sign related to chronic retinal hypoperfusion. METHODS: A case report of a 42-year-old woman who was found to have a novel pattern of retinal vascular remodeling in the setting of severe bilateral occlusive disease of the carotid and vertebral arteries. RESULTS: The patient had a childhood history of nasopharyngeal carcinoma, treated with external beam radiation. At age 35, she suffered bilateral occipital infarctions. A cerebral angiogram showed complete occlusion of both common carotid arteries and complete occlusion of the proximal segments of both vertebral arteries. Seven years after her stroke, examination of her fundus revealed a remarkable pattern of vascular remodeling that involved nearly all of the major retinal arterioles in both eyes. In each vessel, a narrowed proximal segment abruptly dilated to a larger-than-normal caliber at a distance of 1 to 2 disk diameters from the optic disk. The abnormally increased caliber extended into the retinal periphery. CONCLUSION: Chronic severe retinal hypoperfusion due to profound carotid occlusive disease can lead to adaptive remodeling of the retinal vasculature in a pattern that closely resembles the iconic image of a pirate's peg leg.

Color vision in anterior ischemic optic neuropathy.

PURPOSE: The non-arteritic form of anterior ischemic optic neuropathy (AION) is the most common acute optic neuropathy among individuals over the age of fifty, yet little is known about how the disorder affects color vision. We tested the hypothesis that color vision correlates with visual acuity in patients with non-arteritic AION. We also evaluated the patterns of visual field loss in a subgroup of patients who manifested relative sparing of color vision. OBSERVATIONS: Records of forty-five patients with non-arteritic AION who had been evaluated at Duke University over a consecutive four-year period were reviewed retrospectively. Statistical analysis of the relationship between color vision and visual acuity was carried out using a linear regression model. Color vision tended to correlate with acuity with respect to visual acuities between 20/16 and 20/63. However, nine patients were identified in whom color vision was relatively spared in comparison with acuity. Most of the affected eyes in this subgroup had a distinctive pattern of visual field loss consisting of a dense, steep-walled cecocentral defect centered below the horizontal meridian. CONCLUSIONS AND IMPORTANCE: In patients with non-arteritic AION, color vision tends to correlate with visual acuity for acuities better than 20/70. Sparing of color vision relative to acuity, a heretofore unreported finding in AION, occurs in approximately 15% of cases. Sparing of color vision reflects damage to foveal projections coupled with preservation of extrafoveal macular projections. The results of color vision testing in patients with non-arteritic AION help to differentiate this condition from other optic neuropathies such as optic neuritis.