Preoperative Iris Rubeosis and Diabetic Vitrectomy Results

Six hundred and forty-five patients undergoing pars plana vitrectomy for diabetic retinopathy without preoperative iris rubeosis were followed for six months and compared with 69 patients that had preoperative pupillary rubeosis and 30 patients that had preoperative peripheral iris and/or angle rubeosis. Preoperatively, the patients' general characteristics were quite similar, but those cases with peripheral iris rubeosis had poorer visual acuities due to a higher incidence of dense vitreous hemorrhages (70%), as compared with those without rubeosis (56%), and a higher incidence of cataracts and prior cataract surgery. The operative procedures were complicated by retinal holes in 40% of the cases with peripheral rubeosis compared with 24% of those without rubeosis. Postoperatively, elevated intraocular pressures occurred in 67% of the cases with preoperative peripheral rubeosis compared with 58% of those with preoperative pupillary rubeosis and 37% of those without preoperative rubeosis. Postoperative steroids were required more frequently in those eyes with preoperative rubeosis. Six months after vitrectomy, the visual results were much better in those eyes without preoperative rubeosis, but 27% of the cases with preoperative peripheral rubeosis had obtained 6/60 visual acuity or better. As expected, there was a direct correlation between the extent of iris rubeosis at the preoperative examination and at the six-month postoperative examination. Regression of preoperative rubeosis definitely occurred in some eyes during the postoperative period. Phthisis had occurred or was occurring in 23% of the eyes with preoperative peripheral rubeosis compared with 15% of the eyes without preoperative rubeosis or with rubeosis confined to the pupil. Determination of the exact incidence of neovascular glaucoma during the six-month follow-up period was difficult, but was probably 33% for those cases with preoperative peripheral rubeosis, as compared with 17% for those without preoperative rubeosis.Opacities of the anterior segments prevented evaluation of more posterior structures in many cases, especially those with preoperative peripheral rubeosis of which 47% had obscured vitreous cavities, as compared with 20% of those without preoperative rubeosis. Of those that could be visualized, the vitreous cavities were usually clear and the retinas attached.