[Different outcome among eyes with proliferative diabetic retinopathy indicated for vitrectomy]

The postoperative outcome was evaluated in each group of surgical indications of vitreous surgery for proliferative diabetic retinopathy (PDR), to investigate the factors responsible for postoperative visual prognosis.

Primary vitrectomy was performed in 119 eyes of 92 patients with PDR. Average postoperative follow-up period was 19 months. The indications for vitrectomy included vitrous hemorrhage in 58 eyes, macular tractional retinal detachment in 17 eyes, extramacular tractional retinal detachment in 10 eyes, macular heterotopia in 11 eyes, and progressive fibrovascular proliferation in the posterior fundus in 23 eyes.

The visual acuity finally improved by 2 lines or more in 91 eyes (77%), remained unchanged in 10 eyes (8 %), and decreased by 2 lines or more in 18 eyes (15%). Final postoperative visual acuity was significantly better in cases of vitreous hemorrhage or progressive fibrovascular proliferation in the posterior fundus than in others. Preoperative rubeosis iridis and macular tractional retinal detachment were probably responsible for the final visual impairment, and intraocular tamponade affected the difference in visual prognosis between the groups of surgical indication. Multivariate analysis in all cases revealed that factors influencing visual outcome were preoperative rubeosis iridis and anemia.

Rubeosis iridis and macular tractional retinal detachment were prognostic factors of the surgery. Vitrectomy for PDR may be effective in improving postoperative visual acuity if performed in the early stage of progressive fibrovascular proliferation in the posterior fundus after sufficient retinal photocoagulation.