REMOVAL OF THE INTERNAL LIMITING MEMBRANE DURING MACULAR HOLE SURGERY

The recommended treatment for full-thickness macular holes is removal of the posterior hyaloid and sometimes the epiretinal membrane from th e retina during vitrectomy in order to release the assumed intravitreo us traction. We have employed a technique involving the additional rem oval of the membrana limitans interna (MLI) from the retina in the vic inity of the macular hole. We report on our clinical results and ultra structural findings. Materials and methods: Between December 1995 and July 1996, we performed vitrectomies on 39 eyes of 37 patients with fu ll-thickness macular hole. After removal of the attached posterior hya loid, a specially developed forceps was used to remove a circular area of the MLI approximately three to four disc diameters in size. At the conclusion of the operation, 20% C3F8 gas was injected and the patien t instructed to stay in a prone position for 8 days. Results: Intraope ratively, ''rhexis'' of the MLI only rarely produced bleeding or recog nizable retinal edema. Complete closure of the hole was observed posto peratively in 36 of the 39 eyes (92%). A visual improvement of at leas t two lines was achieved in 77% of eyes with successful closure. Pigme nt irregularities or edematous changes could not be detected either cl inically or by fluorescein angiography in any of the 39 eyes. Electron microscopy was performed on 23 of the membranes. The salient feature was the MLI. Canals leading from the inner to the outer surface of the MLI contained Muller cell processes with clear signs of necrosis or d egeneration. On the vitreous side, the MLI usually exhibited myofibrob lasts. Conclusions: The MLI was successfully removed in all 39 eyes wi th a full-thickness macular hole. This procedure led to very good anat omic and functional results. It remains for future studies to determin e the pathogenic significance of the necrotic processes detected by el ectron microscopy in the MLI canals.