Abstract
Abstract: :
Purpose: To evaluate the ultrastructure of the inner limiting membrane (ILM) and epiretinal tissue in stage III and stage IV idiopathic macular holes. Methods: Pars plana vitrectomy with en–bloc removal of the ILM and epimacular tissue was performed by one surgeon in 73 eyes with stage III and 27 eyes with stage IV macular holes. Posterior vitreous detachment (PVD) was diagnosed at the beginning of surgery. In total, 232 specimens of 100 eyes were processed for light and transmission electron microscopy. Results: In 36 eyes with stage III macular holes and in 7 eyes with stage IV macular holes, the ILM was devoid of any cells and collagen. Fibrocellular proliferation was found at the vitreal side of the ILM in 57 cases. Fibrous astrocytes, myofibroblasts, fibroblasts, and macrophages were observed in descending order. Native vitreous collagen (NVC) was attached to the ILM in 38 cases. The presence of NVC was significantly more frequent in eyes with stage IV macular holes (63%) than in eyes with stage III macular holes (29%). Mono– and multilayered cellular membranes were seen more frequently in stage IV macular holes. NVC if present was always associated with fibrocellular proliferation. In eyes with a continuous layer of NVC, there were mostly multilayered cellular membranes. Conclusions: In ultrastructural terms, the severity of fibrocellular proliferation is associated with the presence of NVC. Incomplete PVD and vitreoschisis may contribute to the development of epimacular membranes in eyes with macular holes. Fibrocellular proliferation appears to be rather a secondary event than a primary feature in macular holes.
Keywords: macular holes • vitreous • proliferative vitreoretinopathy