Examining the histopathology of ILM flap in macular holes

Dr Ricarda Schumann, of the Ludwig-Maximillians University Hospital, Munich, Germany, shared the results of her research into the histopathology of the inner limiting membrane (ILM) flap in large, idiopathic, full-thickness macular holes at the 17th Annual EURETINA Congress in Barcelona, Spain. The goal was to analyse the cellular characteristics of the ILM in macular hole cases. This is important, as a fragment of the ILM, referred to as the “ILM flap”, is placed into or over the fovea in large macular holes, which are less likely to close without a flap. As such, studying the cell distribution and characteristics of premacular cell proliferation in surgically excised ILM specimens might give insight into how an ILM flap assists in the holes’ closure. The specimens were studied using interference, phase-contrast, immunofluorescence and transmission electron microscopy. A very broad variety of cell density was discovered, including hyalocytes, myofibroblasts and native vitreous collagen. These cells were all found on the ILM’s vitreal side. However, not only cells were found. “This was the first study to demonstrate the presence of neurotrophic factors in the ILM,” said Dr Schumann. These included glial cell-derived neurotrophic factor and ciliary neurotrophic factor, both of which showed high levels of immunoreactivity. Dr Schumann raised the question of whether there might be a possible role for premacular cells and neurotrophic factors in the rehabilitation of retinal architecture and function.