Glaucoma after pars plana vitrectomy and silicone oil injection for complicated retinal detachments

Abstract

Objective To determine the incidence and associations of glaucoma after pars plana vitrectomy (PPV) and silicone oil injection (SOI) for complicated retinal detachments and the response to treatment. Design Retrospective noncomparative case series. Participants A total of 150 eyes of 150 patients who had completed a minimum of 6 months of follow-up were included in this study. Analysis included clinical records of all consecutive cases of complicated retinal detachment that underwent PPV with SOI between July 1991 and February 1996. Intervention Surgical intervention for vitreoretinal pathology included standard three-port PPV and additional procedures as appropriate for the retinal pathology, and SOI. Procedures for the control of glaucoma were silicone oil removal (SOR), trabeculectomy with mitomycin C, cyclocryotherapy, semiconductor diode laser contact transscleral cyclophotocoagulation (TSCPC) and anterior chamber tube shunt to encircling band (ACTSEB). Main outcome measures Presence of glaucoma (predefined as intraocular pressure [IOP] ≥ 24 mmHg, which also was ≥10 mmHg over the preoperative level, sustained for ≥6 weeks) and the result of medical and surgical management were the main outcome measures. Demographic, preoperative, intraoperative, and postoperative parameters including the age of the patient, etiology of retinal detachment, refractive status, pre-existing glaucoma, aphakia, diabetes mellitus, presence of silicone oil (SO) in the anterior chamber, emulsification of SO, rubeosis iridis, and anatomic success were evaluated by univariate and multivariate logistic regression analyses to assess their predictive value in the causation of glaucoma and to determine factors prognosticating response to treatment. Results The main indications for PPV+SOI were proliferative vitreoretinopathy (57%; 85 of 150), proliferative diabetic retinopathy (15%; 23 of 150), and trauma (14%; 21 of 150). Glaucoma occurred in 60 eyes (40%) at 14 days median (range, 1 day–18 months). Elevation of IOP could be attributed directly to SO in 42 (70%) eyes. Glaucoma was controlled in 43 (72%) of 60 eyes on treatment (with medicines alone in 30%; SOR and medicines in 25%; trabeculectomy with mitomycin C/ACTSEB/cyclocryotherapy or TSCPC in 17%); 28% (17 of 60) remained refractory. Independent predictive factors for glaucoma on multivariate analysis were rubeosis iridis (odds ratio, 10.76), aphakia (odds ratio, 9.83), diabetes (odds ratio, 6.03), SO in anterior chamber (odds ratio, 4.74), and anatomic failure (negative risk factor; odds ratio, 0.11). Poor prognostic factors for the control of glaucoma were SO emulsification (odds ratio, 15.34) and diabetes (odds ratio, 6.03). Conclusion Glaucoma is a frequent and often a refractory complication of PPV with SOI and has a multifactorial etiology. Aggressive medical and surgical management with SOR, trabeculectomy with mitomycin C, glaucoma shunts, and cyclodestructive procedures shows modest success in controlling IOP.