Factors for decreased visual acuity following vitrectomy for proliferative diabetic retinopathy

We reviewed 150 eyes of proliferative diabetic retinopathy which underwent vitrectomy during the foregoing 41 months. The follow-up period averaged 20 months. The postoperative visual acuity (VA) improved in 51 eyes (34%), deteriorated after temporary improvement in 70 eyes (47%), remained unchanged in 17 eyes (11%), and deteriorated in 13 eyes (8%). Cases with improved VA were Characterized by lower ages of surgery and of the presumed onset of retinopathy. Cases with permanently improved VA showed lower postoperative values of HbA1C. Cases with unchanged or deteriorated VA showed a higher incidence of rubeosis iridis and macular detachment. Cases with deteriorated VA after temporary improvement had higher values of hematocrit and hemoglobin and lower values of triglycerides than cases with unchanged VA. Cases with unchanged or deteriorated VA showed higher incidences of rubeosis iridis, vitreous hemorrhage or retinal detachment than the other cases. Cases with permanently improved VA showed lesser incidences of preoperative fibrous proliferation in the posterior fundus (p=0.001) and postoperative macular degeneration (p=0.02).