Purpose: To determine the ultrastructural characteristic of the operculum associated with macular holes.
Methods: We developed instrumentation and a technique to capture the operculum observed with macular holes. Two opercula were studied by transmission electron microscopy.
Results: The two specimens were attached to a layer of native collagen identified as cortical vitreous and were composed primarily of Mueller cells and fibrous astrocytes without adjacent inner limiting membrane. No distinct retinal neuronal tissue was present.
Conclusions: Our findings indicate that proliferation of fibrous astrocytes and Mueller cells occurs with the formation of a macular hole, that this reparative tissue may be dislodged, and it is the reparative tissue that previously has been interpreted as an operculum.