To compare anatomic and visual acuity outcomes, as well as complication rates, after retinal detachment repair using 1000-vs 5000-centistoke silicone oil. Methods: Records of all patients who underwent retinal detachment repair with silicone oil at one institution between January 1, 1995, and December 31, 2000, were reviewed. Anatomic outcomes included retinal redetachment and macula-off retinal redetachment. Visual acuity outcomes included ambulatory vision (Ն5/200) and change in visual acuity from preoperative examination. Complications included rates of secondary intraocular pressure elevation, hypotony, corneal opacification, cataract, and oil emulsification. Outcomes were assessed at 1 week, 1 month, 3 months, 6 months, and 1 year. Results: The study included 82 eyes that underwent retinal detachment repair with 1000-centistoke silicone oil and 243 eyes that underwent retinal detachment repair with 5000-centistoke silicone oil. Demographic characteristics, cause of retinal detachment, and preoperative