Abstract
Abstract: :
Purpose:Early histopathologic changes in age-related macular degeneration are characterized by submacular retinal pigment epithelial cell (RPE) atrophy and choroidal vascular degeneration. Previously, we reported on cases of dry age-related macular degeneration (AMD) where RPE atrophy clearly occurred in advance of choroidal capillary changes. In this study, we examined other cases of both dry and wet forms of AMD to further examine the RPE/choriocapillaris relationships in this disease. Methods:Whole human eyes from five donors ranging in age from 75-105 years of age (mean 90.4 years) were obtained from the National Disease Research Interchange 20-30 hours postmortem. Anterior segments were removed and gross photos of the posterior pole were taken prior to dissecting the retina and choroid. Tissues were fixed, incubated for alkaline phosphatase activity, partially bleached and analyzed as described previously (McLeod et al IOVS 43:1986, 2002). Results:As we described previously, eyes that had areas of RPE atrophy, demonstrated choriocapillaris degenerative changes intimately associated with those regions. However, in some eyes, we found choriocapillaris dropout extending well beyond the boundaries of RPE atrophy. In other cases, choriocapillaris degeneration was present in regions without any morphologically changes in the RPE. Most viable choroidal neovascularization had RPE associated with the neovascular formations. Conclusions:RPE atrophy in AMD is always accompanied by choriocappillaris degeneration. However, choriocapillaris dropout can occur in eyes with AMD in the absence of RPE atrophy, which suggests a possible vascular etiology for AMD in some eyes. These observations provide further insights into the symbiotic relationship between RPE and choriocapillaris that is disrupted in AMD.
Keywords: choroid • retinal pigment epithelium • choroid: neovascularization