Electron-Microscopic Study of Diabetic Capillary Aneurysm

Introduction Electron-microscopic studies of tissues from human diabetic patients have proved of great value in understanding the histopathological characteristics of this disease.¹⁻⁴In this present study, the authors successfully demonstrated a saccular and a hyalinized capillary aneurysm of the retina on electron micrographs, as well as in flat preparations and cross-sections of the retina. Material and Methods Thirty-nine eyes of diabetic subjects were obtained from autopsy material and studied on celloidin sections and flat preparations. Celloidin sections were stained with PAS and hematoxylin, and flat preparations were stained with PAS alone. Two surgically removed eyes and 6 eyes obtained at autopsy and presenting diabetic retinopathy were studied with electron-microscopic methods. Surgically removed eyes were immediately fixed in osmic acid, embedded in methacrylate in routine manner and subjected to electron microscopy. Autopsy eyes, which had been preserved in 70% alcohol, were washed overnight, fixed in osmic acid, and then routine