Visual Acuity and Field Loss in Retinitis Pigmentosa-Reply

Abstract

In Reply. —In the article 1 discussed by Dr Marmor, we demonstrated, in 235 patients with typical RP and no evidence of visual acuity-limiting cataract or macular edema, that for patients with visual fields smaller than 30°, the prevalence of decreased visual acuity increases with the extent of further visual field loss. Specifically, until the V-4-e visual field reaches 30°, 96% of patients retained 20/40 visual acuity or better. Fewer than one third of patients with visual fields smaller than 10° radius had visual acuities of 20/40 or better and intermediate percentages of patients with 20/40 visual acuity or better were seen at intermediate visual field sizes. In other studies, 2,3 we showed that visual field loss in RP, regardless of subtype, progresses at a very predictable rate, following an exponential decay function. We appreciate Dr Marmor's interest in our work and are grateful for the opportunity to clarify