Rubeosis iridis and glaucoma associated with sickle cell retinopathy: a light and electron microscopic study.

The ultrastructure of rubeosis iridis in sickle cell-hemoglobin C disease is described for the first time. Findings included open interendothelial cell junctions, intraendothelial cytoplasmic attenuations (fenestrations), and pericyte formation. The ultrastructural appearance of rubeosis iridis gives no clue to the underlying etiology and is similar to that reported in rubeosis associated with diabetes mellitus, central retinal vein occlusion, and uveitis. The electron microscopic findings explain the functional incompetence of rubeotic vessels that are manifested by transmural leakage of fluorescein.