PURPOSE: To investigate the anatomic and functional results of large retinotomies. METHODS: The charts of 33 consecutive patients who underwent peripheral retinotomy of 180 degrees or more and silicone oil injection during vitrectomy for retinal detachment with proliferative vitreoretinopathy were reviewed. Silicone oil was removed from 26 eyes (79%), but 2 hypotonic eyes (6%) required reinjection of silicone. RESULTS: After a minimum follow-up of 6 months, the retina was completely attached in 28 eyes (85%). Twenty-eight eyes (85%) achieved a final visual acuity of 5/200 or better, and seventeen eyes (51%) achieved visual acuity of 20/200 or better. Intraocular pressure did not change significantly from the initial to the final examination. At the last follow-up, hypotony (intraocular pressure < or = 5 mmHg) was seen in 1 of the 28 eyes with reattached retina (3.6%). A new macular epiretinal membrane, related to the duration of silicone oil tamponade, developed and was peeled off in 12 eyes (36%) in an additional procedure. No association could be found between the anatomic or functional results and the extent of the retinotomy. Presented herein is the largest series of retinotomies of 180 degrees or more followed up after silicone oil removal. CONCLUSION: Large retinotomy (> or = 180 degrees) in selected cases of vitreoretinal surgery seems to be an effective procedure.