Abstract
Abstract: :
Purpose:To investigate the morphological changes of the neural retina following the removal of the internal limiting membrane (ILM) in primates. Methods:Pars plana vitrectomy and peeling of the internal limiting membrane were performed in 6 eyes of the 6 cynomolugus monkeys. Scanning electronmicroscopy (SEM) and transmission electronmicroscopy (TEM) were used to investigate the morphologic changes in the exposed inner surface of the neural retina immediately and 3 months after ILM removal. Results:In the three eyes examined immediately after surgery, the removed ILM associated with fragments of the glial tissue was confirmed by TEM. Clusters of damaged glial tissue, probably inner portion of the Muller cells and astrocytes, were considered to be the origin of the glial fragments attached to the peeled ILM. Consequently, some exposed nerve fiber layer, not covered with glial tissue, were also observed in the neural retina by SEM. In the three eyes examined 3 months after removal of the ILM, SEM showed gliosis on the exposed surface of the neural retina, focally forming membrane-like tissue. In some regions, TEM showed thin basement-membrane-like material covering these glial cells, suggesting regeneration of the ILM. In some regions, neuronal axons were still exposed without overlying glial tissue. Conclusion:Mild damage could occur to the neural retina as a result of the removal of the ILM. In 3 months, the exposed neuronal retina was mostly covered with glial tissue and the signs of ILM regeneration was also noted.
Keywords: 628 vitreoretinal surgery • 554 retina • 565 retinal glia