Comparison of morphology of human macular and peripheral Bruch's membrane in older eyes.

Deposits in macular human Bruch's membrane (BrM) increase with age and have been postulated to be associated with age-related maculopathy. We used two ultrastructural methods to compare these deposits by electron microscopy in macular and peripheral BrM of eight eyes from donors 63-86 years of age. Quick-freeze/deep-etch (QFDE) was used to prepare replicas that showed the ultrastructure of deposits, and osmium-tannic acid-paraphenylenediamine (OTAP) was used to preserve small extracellular lipid particles. We found that an accumulation of lipoprotein-like particles (LLPs) occurred in the peripheral BrM just as it does in the macular region, but with perhaps a somewhat slower time course. The "lipid wall," reported in macular BrM, was also found occasionally in the peripheral regions. The same processes that lead to age-related accumulation of LLPs in macular BrM appear to also occur in the peripheral regions.