Autofluorescence imaging in age-related macular degeneration complicated by choroidal neovascularization: a prospective study

Abstract

Purpose: To determine if integrity of the retinal pigment epithelium (RPE)/photoreceptor complex as assessed by autofluorescence imaging can be predicted on the basis of visual acuity (VA), size, or fluorescein angiographic characteristics of the lesion in the early stage of choroidal neovascularization in age-related macular degeneration (AMD).

Design: Prospective, observational, consecutive case series.

Participants: Seventy-nine eyes of 78 patients with untreated early-stage subfoveal neovascular AMD.

Methods: Digital color fundus photography and fluorescein angiography were carried out by certified photographers using the same camera throughout the study. Confocal scanning laser ophthalmoscopy images were obtained using a retinal angiograph. Autofluorescence images were compared with digital fluorescein angiography and fundus color photographs using IMAGEnet.

Main outcome measures: Autofluorescence at the macula was correlated with VA, angiographic lesion characteristics, lesion size, and length of symptoms.

Results: Of the 79 eyes studied, 40 had classic and predominantly classic choroidal neovascularization, 10 had minimally classic, 29 had occult, 75 were subfoveal, and 4 were juxtafoveal. In 54 eyes, autofluorescence was continuous at the central macula, and this correlated significantly with VA, lesion size, and symptom length but not choroidal neovascularization type. However, there was considerable overlap between the 2 groups such that the integrity of RPE autofluorescence could not be predicted on the basis of these criteria.

Conclusion: Intact autofluorescence at the macula in early choroidal neovascularization correlates with VA, lesion size, and symptom length but not lesion type. None predict with any certainty the integrity of the outer retina. Our data suggest that the RPE/photoreceptor complex may be intact at the macula for several months in the presence of choroidal neovascularization, suggesting that VA might be rescued if treatment were effective in suppressing neovascular growth without damaging the RPE/retina complex, although this remains to be tested. It would be sensible to assess autofluorescence in treatment protocols to test this concept because it may be a marker for earlier disease and predict outcomes of treatment.