The Incidence of Retinal Angiomatous Proliferation (RAP) in the Fellow Eye. Updated Findings

Abstract

Purpose: : To report the incidence of retinal angiomatous proliferation (RAP) in the fellow eyes of patients with unilateral RAP.

Methods: : Medical records of all patients with ARMD who underwent treatment for RAP at our Institutions between January 2000 and December 2004 were reviewed. Sixty–two consecutive patients who had been treated in the first eye and whose fellow eye was free of RAP at presentation represented our study population. Clinical biomicroscopic examination, dynamic fluorescein and indocyanine green angiography with stereo angiograms were routinely performed during follow–up examinations using a confocal Scanning Laser Ophthalmoscope ( SLO,HRA–Heidelberg Engineering, Germany). Incidence rates of RAP in the fellow eye were calculated using the Kaplan–Meier method. Frequencies of pre–RAP variables (i.e., choroidal hypofluorescence, reticular drusen and retinal pigment epithelium abnormalities) were tabulated for the study population and evaluated using the chi–square or the Fisher exact test (counts within a category less than 5). Nominal P values were calculated for all comparisons.

Results: : Of the 62 patients (62 eyes), 48 were females and 14 males. Mean age was 78 years. During a mean follow–up of 39 months (range, 6–79), 24 RAP developed in 24 fellow eyes (39%). The incidence of RAP in the fellow–eye was 5% at six months,17% at twelve months and 50% at approximately forty months (i.e., survival time 39,93 ± 2,6 months [mean ± SE]). The incidence of RAP did not change significantly among patients with different stages of RAP in the first eye at baseline (P=.54). An association between pre–RAP variables and RAP development was established for retinal pigment epithelium abnormalities (P=.03).

Conclusions: : Patients affected by RAP in one eye are at risk of developing a new RAP in the fellow eye. Fifty % of the lesions will occur within three years. Increased retinal pigment epithelium abnormalities may predict the future development of RAP and deserve particular attention during follow–up of these patients.

Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • age-related macular degeneration • retinal neovascularization