Previous models of disease in age-related macular degeneration (AMD) were incomplete in that they did not encompass subretinal drusenoid deposits (pseudodrusen), subtypes of neovascularization, and polypoidal choroidal vasculopathy. In addition, Type 3 neovascularization starts in the retina and may not necessarily involve the choroid. As such, the term choroidal neovascularization is not appropriate for these eyes. The new aspects in the AMD construct are to include specific lipoprotein extracellular accumulations, namely drusen and subretinal drusenoid deposits, as early AMD. The deposition of specific types of deposit seems to be highly correlated with choroidal thickness and topographical location in the macula. Late AMD includes macular neovascularization or atrophy. The particular type of extracellular deposit is predictive of the future course of the patient. For example, eyes with subretinal drusenoid deposits have a propensity to develop outer retinal atrophy, complete outer retinal and retinal pigment epithelial atrophy, or Type 3 neovascularization as specific forms of late AMD. Given Type 3 neovascularization may never involve the choroid, the term macular neovascularization is suggested for the entire spectrum of neovascular disease in AMD. In contrast to older classification systems, the proposed system encompasses the relevant presentations of disease and more precisely predicts the future course of the patient. In doing so, the concept was developed that there may be genetic risk alleles, which are not necessarily the same alleles that influence disease expression.
Previous models of age-related macular degeneration did not include subretinal drusenoid deposits, Type 3 neovascularization, or polypoidal choroidal vasculopathy. In a new system, the primary manifestation of early age-related macular degeneration is the accumulation of extracellular deposits. The late phase of disease is manifested by atrophy and macular neovascular disease.
*Vitreous, Retina, Macula Consultants of New York, New York, New York; and
†LuEsther T. Mertz Retina Research Laboratory, New York, New York.
Reprint requests: Richard F. Spaide, MD, Vitreous, Retina, Macula Consultants of New York, 460 Park Avenue, 5th Floor, New York, NY 10022; e-mail: email@example.com
Supported in part by the Macula Foundation, New York, NY.
The author receives royalties and consulting fees from Topcon Medical Systems, royalties from DORC, and has received consulting fees from Heidelberg Engineering.