Trabeculotomy (ab externo) as primary intervention for open-angle glaucoma : 5-year results

Abstract

The published results of trabeculotomy ab externo (TOT), as an outflow channel surgery in adults with open-angle glaucoma, are underrepresented in comparison with other pressure-lowering glaucoma procedures. To determine the long-term pressure lowering effect and complications of TOT as astand-alone procedure or in combination with phacoemulsification with intraocular lens implantation (PIT) as aprimary pressure-lowering procedure in adult patients with forms of chronic open-angle glaucoma. This was aretrospective analysis of 121 eyes of 106 patients wherby 90eyes underwent TOT and 31eyes underwent PIT. The follow-up period was 5years. Follow-up was performed in the same center under standardized conditions. Preoperative as well as postoperative best-corrected distance visual acuity, intraocular pressure, pressure-lowering medication, and complications were recorded. For success criterion1, the intraocular pressure was not allowed to exceed 17 mm Hg at any control. For success criterion2, the intraocular pressure was allowed to be above 17 mm Hg at 1 control throughout the follow-up period. Preoperative intraocular pressure in the TOT group was 25.92 mm Hg (SD 6.58) and 26.32 mm Hg (SD 6.06) in the PIT group. The annual cumulative success rates with pressure-lowering medications for success criterion1 were 92.8%, 82.5%, 70.5%, 52.7% and 26.1%. For success criterion2 these were 97.9%; 94.9%, 93.2%, 91.3%, and 89%. We found no relevant difference in pressure reduction between TOT and PIT. Without pressure-lowering medications, success rates were significantly lower for both success criteria. No serious complications occurred. The most common postoperative complication was spontaneously resorbable hyphema. Performing TOT or PIT as aprimary glaucoma procedure for chronic open-angle glaucoma in adults is reasonable, has a significant pressure-lowering effect and very low complication rate.