Purpose To determine outcomes of ab interno trabeculotomy for treatment of open-angle glaucoma (OAG). Design Retrospective interventional single-surgeon, single-center case series. Methods Data were collected from 246 patients undergoing ab interno trabeculotomy between September 1, 2006, and December 1, 2010, with 3 months' follow-up or longer. Kaplan-Meier analysis was performed using Criteria A (postoperative intraocular pressure [IOP] ≤21 mm Hg or ≥20% reduction from preoperative IOP) and Criteria B (IOP ≤18 mm Hg and ≥20% reduction in IOP). Failure included increased glaucoma medications or subsequent surgery. Failure risk factors were identified using Cox proportional hazards ratio (HR). Results Of 88 cases of ab interno trabeculotomy-only and 158 cases of ab interno trabeculotomy with cataract extraction, the retention rate was 70% for 1 year and 62% for 2 years. Preoperative mean IOP was 21.6 ± 8.6 mm Hg; the number of glaucoma medications was 3.1 ± 1.1. At 24 months postoperatively, mean IOP was reduced 29% to 15.3 ± 4.6 mm Hg (P < 0.001) and the number of glaucoma medications was reduced 38% to 1.9 ± 1.3 (P < 0.001) with a success rate of 62% (95% CI, 56%-68%) using Criteria A and 22% (95% CI, 16%-29%) using Criteria B. Failure risk factors using Criteria A included primary OAG (HR 3.14, P < 0.01, 95% CI, 1.91-5.17) and past argon laser trabeculoplasty (HR 1.81, P < 0.01, 95% CI, 1.18-2.77). Using Criteria B, the HR for pseudoexfoliative glaucoma was 0.43 (P < 0.01, 95% CI 0.27-0.67). Of the cases, 66 (26.8%) required subsequent surgery on an average of 10 months (2 days to 3.2 years) after ab interno trabeculotomy. Conclusions For criteria involving IOP ≤18 mm Hg, the 24-month survival of ab interno trabeculotomy is low. This surgery is appropriate for patients requiring a target IOP of 21 mm Hg or above.
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