CLINICOPATHOLOGICAL CORRELATION OF DRUSEN AND RETINAL-PIGMENT EPITHELIAL ABNORMALITIES IN AGE-RELATED MACULAR DEGENERATION

Background: Clinicopathologic studies of eyes lead to a better underst anding of the nature of the ophthalmoscopic and fluorescein angiograph ic features of drusen. A study was conducted to provide clinicopatholo gic correlation of drusen and present a classification of drusen based on clinical and histopathologic features. Methods: The macular areas of three eyes from two patients were serially sectioned and studied, a nd features were depicted in a two-dimensional map and compared with c linical findings. Results: All three tyes had large drusen (>63 mum) w ith soft morphologic characteristics (poorly demarcated borders) docum ented on fundus photographs. In both eyes from one patient, these larg e drusen corresponded to areas of focal retinal pigment epithelium hyp opigmentation overlying Bruch's membrane, which was diffusely thickene d throughout the macula. Similar findings were noted in another eye fr om a second patient, and additionally, where there was relatively mark ed fluorescein staining of large drusen on the late phase of an angiog ram, the pathologic correlation demonstrated detachment of the thicken ed inner aspect of Bruch's membrane from the remainder of Bruch's memb rane. Focal hyperpigmentation corresponded to areas of hypertrophy of the retinal pigment epithelium and to clusters of pigmented cells in t he subretinal space and outer nuclear area. Conclusion: Diffuse thicke ning of the inner aspect of Bruch's membrane is associated with retina l pigment epithelial hypopigmentation, focal atrophy, and soft (large) drusen formation.