Abstract
Abstract: :
Purpose: Peeling of the retinal internal limiting membrane (ILM) has been introduced as a potentially useful method in various macular diseases. Recently, the visualization of the ILM during surgery was facilitated by the use of indocynanine green (ICG). Consequently, ILM peeling is widely used in macular hole surgery. The study was performed to examine the ultrastucture of the retina after ICG assisted peeling of the ILM. Methods: We performed a standard three port pars plana vitrectomy in human cadaver eyes. A core vitrectomy with posterior vitreous detachment was performed. Thereafter, we injected 0.25% ICG solution into the posterior vitreous cavity over the macula. The ICG was removed with a fluid needle leaving the ILM nicely stained with indocyanine green. Then, an initial ILM tear was produced using an endgripping vitreous forceps, and the ILM was peeled around the fovea. At the end of the procedure the eyes were perfused with buffered 2.5 % glutaraldehyde, rinsed in buffer, postfixed in 1% osmium tetroxide, dehydrated in acetone cascade, and embedded in epoxy resin. Specimens were submitted for electron microscopy. The study was approved by the local Ethical Committee. Results: Electron microscopy confirmed minimal post-mortal retinal damage. In the peeled area the ILM was totally removed. Adjacent to this area the ILM was slightly elevated and separated from the underlying tissue. Within the peeled area a significant number of Müller (glial) cell endfeet and vitread Müller cell processes was damaged. There was no evidence of damage in deeper retinal layers. In areas remote to the peeled area no ultrastructural damage was observed. Conclusions: Our study demonstrates that ICG assisted peeling of the ILM results in moderate ultrastructural damage of Müller cell processes but no significant disturbances of deeper retinal layers within the peeled area. Probably, the damage of Müller cell processes is a stimulus for glial regeneration. This finding is consistent with the clinical finding that removal of the ILM in macular hole surgery results in a high rate of anatomic success and is not associated with visual loss.
Keywords: macula/fovea • vitreoretinal surgery • macular holes