Vitreoretinal and anterior segment surgery through the pars plana: part I

Instrumentation and clinical experience dealing with intraocular surgery through a pars plana approach have advanced rapidly during the past 5 years. These techniques have been used to successfully treat a number of ocular disorders. Considerable experience with this form of surgery has accumulated, and the results and incidence of complications are similar among centers. Additional refinements in instrumentation and surgical techniques will probably expand the capabilities and further improve the results of pars plana surgery. However, we are rapidly approaching a point at which the primary limiting factor will be the pathophysiology of ocular diseases rather than instrumentation or surgical skill. The ability to improve vision by removing persistent opacities of the ocular media has been demonstrated, and follow-up of 2 more years has shown that the eye can continue to function well after excision of the formed vitreous. The indication for vitreous surgery which has proven to be the most difficult and hazardous is treatment of complicated rhegmatogenous retinal detachments in which elevated, mobile retina presents special problems. The role of vitrectomy in the management of proliferative diabetic retinopathy and early management of penetrating injuries involving the posterior segment are the primary clinical-research objectives for the immediate future. In these conditions vitrectomy may be useful to alter the course of progressive vitreoretinal pathology as well as being used to treat previously existing complications. Finally, our experience has shown that risk of significant complications is present in every case of surgery performed through a pars plana approach. The incidence of mechanical complications can be minimized by careful attention to detail during surgery, but complications cannot be eliminated. Retinal detachment is the most frequent potentially blinding complication, and the vitreous surgeon should be skilled in management of retinal breaks and retinal detachment. Also, there are biologic complications, including rubeosis iridis, which may occur following technically successful surgery in certain eyes. Rubeosis iridis is a major problem in diabetic eyes because it can destroy the functional results of an otherwise successful operation, and no effective treatment is now known. Hopefully, research efforts will improve our understanding of the pathogenesis of this disorder and permit us to develop effective means of prophylaxis or treatment.