Alteration of the Blood-Retinal Barrier Identified by Retinal Leakage Analysis Is a Predictor for Conversion to Wet Age-Related Macular Degeneration

Abstract

Purpose: : To identify in a longitudinal and observational study the occurrence of alterations of the outer Blood-Retinal Barrier (BRB), i.e., the Retinal Pigment Epithelium (RPE) barrier, and their relation with the development of choroidal neovascularization (CNV) lesions.

Methods: : Fifty-nine patients with unilateral CNV and early age-related maculopathy in the study eye have been followed in an ongoing observational, longitudinal study. These patients have a particularly high risk of developing CNV in the fellow eye, the study eye. Examinations were performed at baseline and every 6 months thereafter. To characterize and identify CNV development we performed best corrected ETDRS visual acuity (VA), optical coherence tomography (OCT), fluorescein (FA) and indocyanine green angiography (ICG), fundus photography (FP) and fundus autofluorescence imaging (FAF). Scanning laser fluorescein angiography (SLOFA) data was further analyzed for Retinal Leakage Analysis (RLA) using methods and proprietary software developed by our research group (Bernardes, IEEE-TBME, 2005). The observations made in the study eyes that did develop CNV during the follow-up are reported.

Results: : Twenty-five of the 59 patients completed 18 months of follow-up at the time of this report. Eight developed CNV in the fellow eye during this period. VA loss and signs of alterations in the SLO.FA were used to identify conversion to wet age-related macular degeneration (AMD). RLA demonstrated the presence of varying degrees of alteration of the BRB in every eye that developed CNV well before conversion with processing failure in only one eye. The alterations of the BRB could be demonstrated in four eyes at every visit before the conversion visit and in the other three in the visit before conversion visit.

Conclusions: : Fellow eyes of patients with wet AMD in other eye that developed CNV during the study showed alterations of BRB, identified by RLA Analysis (SLO.FA), before conversion. Alterations of BRB appear to predict development of CNV.

Keywords: age-related macular degeneration • choroid: neovascularization • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)