A Simple Clinical Scale for Estimating the Risk of Age–Related Macular Degeneration Progression

Abstract

Abstract: : Purpose: To develop a simple clinical scale for assessing a patient's 5–year risk of developing advanced age–related macular degeneration (AMD). Methods: Based on long term follow–up of 3,211 participants in the Age–Related Eye Disease Study (AREDS), 5–year rates of developing advanced AMD (neovascular AMD or central geographic atrophy in one or both eyes) were cross classified by two easily recognizable clinical features characteristic of AMD (drusen size and any pigment abnormalities). Cells in this table with similar rates were combined to create a 5–step scale. Results: The following risk factor scoring system was developed. Assign to each eye one risk factor for "presence of one or more drusen at least as wide as a vein width at the disc margin (about 125 microns)" and one risk factor for "presence of any pigment abnormality." The risk factors for both eyes are then summed, resulting in a 5–step scale ranging from zero to four, on which the approximate 5–year risk of developing advanced AMD in at least one eye increases in the following easily remembered sequence: 0 factors: 0.5%, 1 factor: 3%, 2 factors: 12%, 3 factors: 25%, and 4 factors: 50%. For persons with no large drusen in either eye, presence of one or more intermediate drusen (between ½ and 1 vein width at the disc margin) in both eyes counts as 1 risk factor. For individuals with neovascular AMD in one eye, the risk of progression in the fellow eye can be estimated by assigning a score of 2 to the advanced eye and assigning 1 or 2 additional risk factors based on the presence of large drusen and/or pigment abnormalities in the contralateral eye. Conclusions: A simplified clinical scale for assessing the 5–year risk of developing advanced AMD, based on gradings of stereoscopic color fundus photographs, provides convenient risk categories based on easily recognizable retinal abnormalities.

Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: natural history