Comparison of silicon oil removal with various viscosities after complex retinal detachment surgery

BACKGROUND Despite the progress in vitreoretinal surgery and the importance of silicone oil as an adjunct for the treatment of complex forms of retinal detachment, controversy still surrounds the issue of selecting the proper oil viscosity for clinical use. Herein, we evaluate the outcomes of retinal detachment (RD) surgery after removing silicone oils of different viscosities. METHODS In this retrospective cohort study, eighty-two eyes with surgically re-attached retinas, of which 53 were filled with 5000 cs silicone oil and 29 with 1000 cs silicone oil were enrolled. We evaluated the outcomes and complications following silicone oil removal. Final anatomic success (stable re-attachment), final visual acuity (VA) and intraocular pressure (IOP)were recorded and analysed. RESULTS Of 82 eyes, 41 had proliferative vitreoretinopathy (PVR), 24 were associated with intraocular foreign bodies, 10 had endophthalmitis and 7 had proliferative diabetic retinopathy with tractional retinal detachment. Prior to silicone oil removal, the retina was attached in all eyes, 29% had VA > or = 6/120 and 52% had IOP > or = 21 mmHg. After silicone oil removal, the retina remained attached in 59(72%) of the eyes, 34% had VA > or = 6/120 and 9% had IOP > or = 21 mmHg. Comparing 1000 cs and 5000 cs silicone oil filled eyes, redetachment occurred more frequently in the latter group especially in cases with associated PVR. Final VA worse than 6/120 was associated with initial VA < 6/120 (OR = 32.2 95%CI 7.4-140.2) and use of 5000 cs silicone oil (OR = 7.9 95%CI 1.9-32.2). No factor was significantly associated with final IOP > or = 21 mmHg. CONCLUSION In complicated retinal detachment surgery, use of 5000 cs silicone oil may be associated with a poorer anatomic and visual outcome compared with 1000 cs silicone oil. However there was no difference between the two viscosities in IOP elevation. A randomized controlled study is necessary to further evaluate such a possibility.