Idiopathic macular holes: Ultrastructural aspects of surgical failure

Purpose: To investigate the ultrastructure of the internal limiting membrane (ILM) and epiretinal tissue in eyes with idiopathic macular holes that were not successfully closed by one operation. Methods: A second vitrectomy with en bloc removal of the ILM and epimacular tissue was performed in 16 eyes with full-thickness macular holes after surgical failure. The specimens were processed for transmission electron microscopy. In 5 of 16 eyes, specimens of first macular hole surgery were also analyzed. Results: Fibrocellular proliferation at the vitreal side of the ILM was found in all specimens from second vitrectomy. Myofibroblasts and fibroblasts were predominant. Cells were frequently observed as irregular accumulations rather than regular multilayers at the ILM. Masses of newly formed collagen were found distributed between cells and ILM. All specimens from first macular hole surgery were characterized by regular cellular layers and the presence of native vitreous collagen. Conclusions: Eyes with idiopathic macular holes that were found not to be closed early after the first vitrectomy show massive proliferation of cells and newly formed collagen irregularly distributed at the remaining ILM. After surgical intervention, ILM remnants and collagen may represent a stimulus for the early formation of tangential traction preventing successful macular hole closure.