EFFECT OF LEVODOPA AND CARBIDOPA ON RECOVERY OF VISUAL FUNCTION IN PATIENTS WITH NONARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY OF LONGER THAN 6 MONTHS DURATION

PURPOSE: We conducted a pilot clinical trial to determine the efficacy of levodopa in promoting visual recovery in eyes with nonarteritic an terior ischemic optic neuropathy of greater than six months' duration. METHODS: This prospective, randomized, double-masked, placebo-control led clinical trial involved 20 subjects with nonarteritic anterior isc hemic optic neuropathy of 30 months' mean duration. Subjects were rand omly assigned to receive either low dose levodopa and carbidopa or a p lacebo for three weeks. At 12 weeks after the baseline visit, the levo dopa group then was provided a higher, conventional dose of levodopa a nd carbidopa for three more weeks. Change in visual function was monit ored at four, 12, 16, and 24 weeks after the baseline visit. RESULTS: At 12 weeks after the baseline visit, the levodopa group experienced a significant (P = .016) mean difference in improvement of visual acuit y of 5.9 letters from the placebo group. At 24 weeks after the baselin e visit, a significant treatment effect (P = .036) for visual acuity w as still evident; the levodopa group had a mean gain in improvement of 7.5 letters difference from baseline from the placebo group. Three su bjects in the levodopa group experienced a doubling of the visual angl e as denoted by a gain of at least 15 letters. Significant improvement was not observed for color vision (P = .82) or mean deviation of visu al field loss (P = .82). CONCLUSION: The study found significant impro vement of visual acuity among subjects receiving levodopa and carbidop a despite long-standing visual loss from nonarteritic anterior ischemi c neuropathy. Confirmation of our results is awaited from larger popul ation studies and with a longer follow-up time interval regarding the efficacy of levodopa in reversing visual loss in this disease.