[Long-term visual prognosis after successful vitrectomy for proliferative diabetic retinopathy]

We evaluated visual prognosis in 50 eyes of 47 patients which underwent successful vitrectomy for proliferative diabetic retinopathy and were followed for more than five years. It was found that the latest visual acuity was worse than the best visual acuity by more than three lines after vitrectomy in 14 eyes (28%) except for the eyes with decreased vision due to cataract. The causes of decrease in visual acuity were optic atrophy in seven eyes, macular degeneration in five eyes, branch retinal vein occlusion in one eye, and submacular hemorrhage in one eye. Risk factors for postoperative decrease in visual acuity were thought to be preoperative macular detachment, subretinal proliferation, and postoperative high intraocular pressure. Therefore, even after successful vitrectomy, there is some risk that the best postoperative visual acuity may deteriorate in cases with severe preoperative retinopathy with these risk factors. This finding suggests that the vitrectomy should be performed before the development of these risk factors for the maintenance of good postoperative visual acuity.