Nature and risk of neovascularization in the fellow eye of patients with unilateral retinal angiomatous proliferation

Purpose: To determine the nature and risk of neovascularization in the fellow eyes of patients with unilateral retinal angiomatous proliferation (RAP), a neovascular form of age-related macular degeneration (AMD). Methods: A consecutive series of 52 patients diagnosed with unilateral RAP were studied retrospectively. Clinical biomicroscopic examination, fluorescein angiography, and inclocyanine green angiography were used to evaluate all patients for the development of neovascular manifestations in the fellow eye. Results: Neovascularization developed in the fellow eye in 52 patients over the follow-up period (range, 2-36 months). All patients developed neovascular manifestations of RAP in the fellow eye. Twenty-one patients (40%) developed a RAP lesion within 1 year; 29 (56%), within 2 years; and 52 (100%), within 3 years. At the time of diagnosis of neovascularization in the fellow eye, 8 patients (15%) had a stage I RAP lesion, 36 (70%) had a stage II RAP lesion, and 8 (15%) had a stage III RAP lesion. Other characteristic findings in these patients included the presence of preretinal, intraretinal, and subretinal hemorrhages in 49 patients (94%) and pigment epithelial detachments in 41 patients (79%). Conclusions: In patients diagnosed with unilateral RAP lesions, the form of neovascularization that develops in the fellow eye is virtually always RAP. The annual and accumulative risk of neovascularization in the fellow eye is higher in patients with RAP than in those with other forms of neovascular AMD. These new findings enhance our understanding of the clinical spectrum of RAP in terms of its natural course and visual prognosis and may possibly offer useful information to establish future treatment options.