Assesment of the Retinal Pigment Epithelium Integrity Using Autofluorescence in Early Stage of Choroidal Neovascularisation in Age–related Macular Disease (AMD)

Abstract

Abstract: : Purpose: The cause of visual loss due to choroidal neovascularisation (CNV) as a complication of AMD is unclear, but is considered to be due to physical disruption or metabolic dysfunction of the retinal pigment epithelium (RPE) with consequent photoreceptor loss. In this study we evaluated the integrity of the RPE in early stages of CNV by analysing the autofluorescence images and comparing them to the colour photos and fluorescein angiography (FFA). Then we correlated the autofluorescent images (AF) to the visual acuity data and length of history. Methods: 67 eyes of 67 patients with AMD and symptoms of 2 years or less were studied. Digital colour fundus photography and fluorescein angiography was carried out by certified photographers using the same Topcon camera. The cSLO images were obtained using a Heidelberg Retinal Angiograph. The images were of a variable, but gradable quality. Grading was performed using a revised version of the grading system established by the International ARM Epidemiology Study. Results: We recorded 37 cases of classic and predominantly classic CNV, 10 cases of minimally classic and 20 occult membranes; 58 of them were subfoveal. The visual acuity was 6/6 – 6/18– 1/60. The distribution of AF varied from patient to patient. In the majority there was intact AF in the central macula that could not be predicted accurately on the basis of visual acuity or length of history. Conclusions: Patients with a recent onset of exudative AMD demonstrated a well preserved RPE AF for long periods that did not correlate well with visual acuity or length of symptoms. Neither poor visual acuity nor length of history in these patients indicates physical loss of RPE. Poor outcome of treatment of CNV may not be due to loss of RPE integrity prior to treatment. Assessing the RPE with the confocal scanning laser ophthalmoscope in patients with AMD would be in guiding therapy. AF imaging should be incorporated into treatment trials to record .

Keywords: age-related macular degeneration • neovascularization • visual acuity