Aim: To analyze the ultrastructural features of epimacular tissue removed during idiopathic macular hole (IMH) surgery and to compare them with those of idio- pathic epimacular membranes. Methods: Three consecutive patients with unilateral stage 3 IMH underwent pars plana vitrectomy with surgical removal of delicate gelatinous membranous epi- macular tissue. One patient was previously treated with laser photocoagulation. The excised material was investigated by means of light and transmission electron microscopy. Results were compared with the findings of the excised material in two idiopathic epimacular membranes. Results: The excised material included variable proportions of cellular and mem- branous material. Glial cells (Müller cells, fibrous astrocytes) and fibroblast-like cells dominated in the cellular component both in the specimens from IHM eyes and in the comparative material. Neural elements were revealed in two of three specimens from IMH eyes. Membraneous material was formed by fragments of internal limiting membrane.Conclusions: Dominance of the glial cells in the cellular component of epimacular formations may reflect the important role of these cells both in formation and in healing process of IMH. The presence of neural elements in the removed epima- cular tissue suggests that, at least in some cases, IMH surgery with peeling of an epimacular membrane can be associated with some injury of the macula.

        Key words: idiopathic macular hole, epimacular membrane, ultrastructure.