Purpose: To evaluate the ultrastructure of the vitreoretinal interface in stage III and stage IV idiopathic macular holes.
Design: A consecutive observational case series, laboratory investigation.
Methods: Pars plana vitrectomy with en-bloc removal of the internal limiting membrane (ILM) and epimacular tissue was performed by one surgeon in 80 eyes with stage III macular holes and in 20 eyes with stage IV macular holes. In total, 218 specimens were processed for light and transmission electron microscopy.
Results: Fibrocellular proliferation at the vitreal side of the ILM was found in 57 cases. Native vitreous collagen (NVC) was attached to the ILM in 36 eyes. The presence of NVC was considerably more frequent in eyes with stage IV (70%) than in eyes with stage III macular holes (26%). Mono- and multilayered cellular membranes were seen more frequently in stage IV macular holes. NVC, if present, was always associated with fibrocellular proliferation. In 39 eyes with stage III and in four eyes with stage IV macular holes, the ILM was devoid of any cells and collagen.
Conclusions: Fibrocellular proliferation appears to be a secondary event instead of a primary feature in macular hole development. The severity of fibrocellular proliferation is associated with the presence of NVC. Incomplete vitreoretinal separation may contribute to the development of epimacular membranes in eyes with idiopathic macular holes. Remnants of the vitreous cortex remain more often attached to the ILM in eyes with spontaneous posterior vitreous detachment (PVD) than in eyes with surgical PVD induction.