Pores of the inner limiting membrane in flat-mounted surgical specimens.

PURPOSE: To demonstrate the incidence of pores in the inner limiting membrane (ILM) in flat-mounted ILM specimens and to show the immunocytochemical properties of cellular proliferation associated with them. METHODS: One hundred and twelve ILM specimens from patients with idiopathic macular holes were flat mounted and screened for pores. The ILM was assessed by phase-contrast and interference microscopy. Various antibodies were used against glial cells, hyalocytes, and retinal pigment epithelial cells. RESULTS: In total, only three pores were found. They were characterized by a full-thickness defect of the ILM with irregular borders and cellular proliferation on the ILM. Glial cells were seen in direct association with the ILM pore. Glial cell and hyalocyte markers were the main immunologic features observed. CONCLUSION: Inner limiting membrane pores are a rare finding. Glial cells are likely to cross the ILM through these pores on their way from the retina to the vitreoretinal border. Given the frequency of cellular proliferation and the rare finding of ILM pores, other pathways have to be considered in playing the leading role in epiretinal proliferation. They might include migration of cells through ILM thinning along retinal vessels and proliferation of vitreous cortex hyalocytes at the vitreoretinal border.