Clinicopathologic correlations in diabetic retinopathy. II. Clinical and histologic appearances of retinal capillary microaneurysms.

One eye of a 21-year-old patient with proliferative diabetic retinopathy was available for clinicopathologic correlation. The fluorescent spots in a fluorescein angiogram were correlated with the changes in color fundus photographs and with the corresponding histologic findings in a trypsin digest preparation of the retina. A round, regular fluorescent spot was the most reliable diagnostic indicator of retinal capillary microaneurysms, although some microaneurysms appeared as irregular fluorescent spots, tiny fluorescent spots, or dark silhouettes with or without fluorescent halos. Very large fluorescent spots correlated with very large irregular pouches that may represent intraretinal neovascularization. Fluorescein angiography was considerably more sensitive than color fundus photography for the detection of retinal capillary microaneurysms.