ABSTRACT
BACKGROUND: Using high-resolution spectral domain optical coherence tomography (SD-OCT), morphologically different types of epiretinal tissue can be distinguished in lamellar macular holes (LMH) and macular pseudoholes (MPH). OBJECTIVE: This article presents the results of histopathological characterization and differentiation of epiretinal tissue in eyes with LMH and MPH, which are classified based on a morphological differentiation in SD-OCT. MATERIAL AND METHODS: This review is based on the currently available literature and own data analyses. Using SD-OCT, a differentiation into hyporeflective epiretinal tissue and contractile epiretinal membranes (ERM) was performed. For fluorescence and transmission electron microscopic analyses, epiretinal tissue harvested by pars plana vitrectomy and peeling of epiretinal tissue was processed. RESULTS: By SD-OCT hyporeflective tissue appears as a thick homogeneous layer of hypodense material located directly on the surface of the inner retina and has no visible signs of traction. Using immunocytochemistry, hyalocytes and glial cells showing no contractile activity are dominant; however, in contractile ERM in MPH, anti-alpha SMA-positive myofibroblasts are predominantly found representing the contractile element. CONCLUSION: The results of ultrastructual investigations demonstrate that morphological cell components of hyporeflective epiretinal tissue from LMH have less contractile properties than cells of contractile ERM. It can therefore be assumed that there are differences in the pathogenesis of epiretinal cell proliferation in LMH. Histopathological investigations support the hypothesis that hyporeflective epiretinal tissue represents modified material from the outer layer of the vitreous body.
