ULTRASTRUCTURAL-CHANGES IN THE TRABECULAR MESHWORK OF HUMAN EYES TREATED WITH CORTICOSTEROIDS

Objectives: To study the ultrastructure of the trabecular meshwork in human eyes with corticosteroid-induced glaucoma and to determine wheth er the changes noted also occur in the eyes of patients with primary o pen-angle glaucoma (POAG) who have been treated with corticosteroids. Methods: The trabecular meshwork from 5 patients in wham corticosteroi d-induced glaucoma was diagnosed and from 6 patients with POAG who had been treated with systemic or topical corticosteroids for months to y ears was investigated with light and electron microscopy. None of the eyes with POAG were considered to have corticosteroid-induced elevatio n of the intraocular pressure. Results: Eyes with corticosteroid-induc ed glaucoma had the accumulation of extracellular material distinct fr om the sheath-derived plaques typical of POAG. A fingerprintlike arran ged material resembling basement membranes (FBM material), considered characteristic of corticosteroid-induced glaucoma, was found in all ey es with corticosteroid-induced glaucoma. In addition, an abnormal accu mulation of densely packed, fine fibrils immediately beneath the inner wall endo thelium of Schlemm's canal was present. The findings were s imilar among patients receiving topical or systemic treatment and amon g patients of different ages. In the eyes from donors with POAG who ha d been treated with corticosteroids, the fine fibrillar material and F BM material were present in small amounts in 3 of 6 donors and were no t found in the other 3 donors. Conclusions: The extracellular material that accumulates in eyes with corticosteroid-induced glaucoma differs from that seen in eyes with POAG. Eyes with POAG exposed to long-term corticosteroid treatment did not all respond with the formation of th e abnormal extracellular, materials characteristic of those found in e yes with corticosteroid-induced glaucoma.