The authors treated 53 patients with uncontrolled glaucoma in silicone oil filled eyes with high intensity focused ultrasound. The silicone oil filled eyes present unusually difficult problems in glaucoma management, since the silicone oil rapidly obstructs filtration openings, and laser techniques have not been effective. The mean pretreatment pressure was 34.2 mmHg. The patients were followed for a mean of 17 months. Seventy-five per cent of ultrasound treated eyes had successful reduction of intraocular pressure to below 20 mmHg with or without concomitant medical treatment at two years after treatment. The complication rate was low in this group of eyes. Five eyes developed hypotonia and three eyes had full thickness scleral perforations but were effectively controlled and developed no other complications during two years of follow-up. This technique appears more effective than cyclo-destructive techniques alone.