Severe proliferative diabetic retinopathy treated with vitrectomy or panretinal photocoagulation: a monocenter randomized controlled clinical trial

Abstract

Objective Visual and anatomic results of pars plana vitrectomy were compared with panretinal photocoagulation in cases of severe proliferative diabetic retinopathy. Design Monocenter randomized controlled clinical trial; randomization and allocation to trial group were carried out by a central computer system. Participants We studied 180 eyes of 180 patients with severe proliferative diabetic retinopathy, half with tractional retinal detachment not involving the macula (n = 90). Some were treated by pars plana vitrectomy (n = 90) and some by panretinal photocoagulation (n = 90). Methods Eyes were randomly divided into 2 groups. Group 1 was treated with pars plana vitrectomy, membrane and internal limited membrane peeling, panretinal photocoagulation, and focal or grid macular laser. Group 2 was treated with panretinal photocoagulation and focal or grid macular laser. Follow-up was at least 12 months. Results Mean preoperative visual acuities and ophthalmic fundus characteristics were compared across groups. A year postoperation, visual acuity (the primary endpoint) in group 1 improved in 30 eyes (33%); was unchanged in 22 eyes (25%); and decreased in 38 eyes (42%). In group 2, visual acuity improved in 32 eyes (35%); was unchanged in 42 eyes (47%); and decreased in 16 eyes (18%). The percentage of improvement in the 2 groups was not statistically significant ( p = 0.75), whereas the stabilized ( p = 0.002) and worsened eyes ( p = 0.0003) in group 1 and group 2 were significantly different. Conclusion In cases of severe proliferative diabetic retinopathy, even with tractional retinal detachment not involving macula, it is best to defer vitrectomy unless definite progression that threatens the vascular center is documented.