Otago glaucoma surgery outcome study : long-term results of uveitis with secondary glaucoma drained by Molteno implants

OBJECTIVE: This study was undertaken in Otago, New Zealand, to provide data on the long-term results of cases of uveitis with secondary glaucoma drained by Molteno implants. DESIGN: A prospective, noncomparative case series of all cases of chronic uveitis with secondary glaucoma drained by Molteno implants from 1978 through 1998. PARTICIPANTS: Forty eyes of 35 patients. INTERVENTION: Insertion of Molteno implant. MAIN OUTCOME MEASURES: Intraocular pressure, visual acuity, and progressive visual field loss. RESULTS: Insertion of a Molteno implant was effective in controlling the intraocular pressure at 21 mmHg or less with a probability of 0.87 (95% confidence interval [CI], 0.76, 0.98) and 0.77 (95% CI, 0.60, 0.93) at 5 and 10 or more years after surgery. The mean visual acuity improved from 20/100 to 20/70 immediately after operation. This value declined to 20/130 at 5 and 10 years after surgery and then improved slightly to 20/120 at 15 years after surgery. In these eyes, the Kaplan-Meier estimated probability of retaining useful vision (visual acuity >20/400; visual field >5 degrees radius) was 0.75 (95% CI, 0.61, 0.89) and 0.71 (95% CI, 0.55, 0.87) at 5 and 7 or more years after surgery. CONCLUSIONS: The insertion of a Molteno implant controlled the intraocular pressure in 76% of cases over the follow-up period. Patients in whom the uveitis was well controlled maintained their visual acuity and visual fields, whereas the proportion of cases requiring steroids and the doses required fell progressively over the period of follow-up. Failures were related to complications of advanced disease, previous intraocular surgery, and failure to control the uveitis. The drainage system provided by the Molteno implant proved robust, continuing to function well despite continuous activity of the uveitis, acute exacerbations of the uveitis, and all subsequent intraocular surgery including cataract extraction, keratoplasty, and vitrectomy.