Age-related macular degeneration histopathologic studies. The 1992 Lorenz E. Zimmerman Lecture

Abstract

Background: Delineation of the morphologic aspects of age-related macular degeneration (ARMD) is helpful in correlation with the clinical features and may contribute to understanding the pathogenesis.

Methods: All eyes on file in the Eye Pathology Laboratory, Wilmer Institute, with the known features of ARMD were analyzed according to age, sex, and race. Methods included routine sections in the macula, stepped-serial and serial sections, and electron microscopy and two-dimensional reconstruction in selected cases.

Results: There were 760 eyes with ARMD from 450 patients. Only 5.3% of these patients were black. Nodular drusen were observed in 6.2% of eyes (n = 47), basal laminar deposits in 54.7%, basal linear deposits in 27.6%, neovascularization in 38.2%, and disciform scars in 40.8%. Three types of soft drusen were identified and were observed in 28.0%. The mean diameter of the disciform scar was 3.73 mm, and mean thickness was 0.27 mm. In disciform scars greater than 0.2 mm in thickness, only approximately 25% of the surface of the scar had some remaining photoreceptor cells. Serous or hemorrhagic detachments were observed in 10.4% of eyes. Retinal pigment epithelial (RPE) atrophy without disciform scars was observed in 24.6% of eyes. Areolar atrophy was the most common feature observed in eyes of black patients.

Conclusion: This comprehensive histopathologic evaluation provides the tabulation of the various morphologic features of ARMD. Basal laminar deposit and basal linear deposit, but not nodular drusen, are important positive associations with choroidal neovascularization, disciform scarring, and visual loss. Preservation of photoreceptor cells was seen only over disciform scars 0.2 mm thickness or less.