Vitrectomy with silicone oil or long-acting gas in eyes with severe proliferative vitreoretinopathy: Results of additional and long-term follow-up - Silicone study report 11

Background: The Silicone Study evaluated the outcomes of vitreoretinal surgery for retinal detachment with proliferative vitreoretinopathy (PVR). Objective: To evaluate short-term (up to 36 months) outcomes in eyes randomized to silicone oil or perfluoropropane gas and long-term (up to 72 months) outcomes in eyes with attached maculas at 36 months. Design: Prospective, randomized, multicentered surgical trial. Setting: Community- and university-based vitreoretinal practices. Patients: Two-hundred sixty-five eyes with PVR randomized to perfluoropropane gas and silicone oil with follow-up through 3 years (cohort 1) and 249 eyes with attached maculas at 36 months (121 eyes randomized to long-acting gas [either sulfur hexafluoride or perfluoropropane] and 128 eyes randomized to silicone oil) with follow-up up to 6 years (cohort 2). Both cohorts consisted of eyes that had and had not undergone vitrectomy for PVR (groups 1 and 2, respectively) before randomization. Of the 265 eyes in cohort 1, 24-month follow-up data were available for 218 eyes (82%) and 36-month follow-up data were available for 196 eyes (74%). Of 208 eyes in cohort 2, 48-month follow-up data were available for 146 eyes (70%), 60-month follow-up data for 119 eyes (57%), and 72-month follow-up data for 73 eyes (35%). Interventions: Vitrectomy surgery for PVR with a long-acting gas or silicone oil as the intraocular tamponade. Main Outcome Measures: Changes in visual acuity, recurrent retinal detachment, and incidence of complications. Results: In group 1 of cohort 1, compared with oil-treated eyes, gas-treated eyes had a higher rate of complete retinal reattachment from 18 to 36 months (P<.05). No other differences were found. In group 2 of cohort 1, no notable differences were found between treatment arms. In cohort 2, during 6 years of follow-up, attachment of the macula was maintained for all eyes. No notable differences in the rates of complete retinal attachment, visual acuity of 5/200 or better, or glaucoma were found between treatment groups. In contrast, gas-treated eyes had more hypotony (P<.001). Silicone oil-treated eyes that underwent subsequent surgery were more likely to have the oil retained (P=.02). Compared with oil-retained eyes, oil-removed eyes had higher rates of complete posterior attachment (P=.01) and of a visual acuity of 5/200 or better (P<.001) and less keratopathy (P<.05). Compared with oil-removed eyes, gas-treated eyes had a worse visual acuity outcome (P<.05) and more hypotony (P<.01). Conclusion: The Silicone Study showed that silicone oil and perfluoropropane gas were equal in most respects for the management of retinal detachments with PVR. Success in the first surgery for PVR is paramount for obtaining better visual results. Overall, surgery for PVR had a high likelihood of retinal reattachment, and if anatomically and visually successful at 3 years, there is an excellent chance that the results will be maintained over the long-term.