Clinical Results of Ab Interno Trabeculotomy Using the Trabectome for Open-Angle Glaucoma: The Mayo Clinic Series in Rochester, Minnesota




In their otherwise well-written article, Ahuja and associates’ conclusions are inconsistent with their data. They report outcomes at 3 months or more using 4 definitions of success from 88 cases of Trabectome-only and 158 cases of combined Trabectome and phacoemulsification. Their outcome success A group included eyes with an intraocular pressure (IOP) of ≤21 mm Hg or ≥20% reduction. Their B group success included eyes with an IOP outcome of 18 mm Hg and ≥20% reduction in IOP. In addition, they included groups C and D, essentially the same as A and B but without additional glaucoma procedures as a failure criterion.


Their subject retention rate was 70% for 1 year and 62% for 2 years. Preoperative mean IOP was 21.6 ± 8.6 mm Hg in the combined 246 cases and the number of glaucoma medications was 3.1 ± 1.1. At 24 months mean IOP was reduced 29% to 15.3 ± 4.6 mm Hg ( P < .001) and glaucoma medications were down 38% to 1.9 ± 1.3 ( P < .001). Statistically significant reductions in IOP lasted up to 36 months after surgery and medications up to 42 months. A 30% reduction in IOP and 40% reduction in medications seem successful to us and consistent with prior reports on Trabectome, some based on voluntary submission of data from the surgeons’ first 20 cases likely to bias results toward failure.


Ahuja and associates’ study included 23 patients (10%) with prior failed trabeculectomy or aqueous tube shunt—a bias toward failure, as such cases are at higher risk for failure. While they are correct in stating there are no randomized trials of Trabectome compared to trabeculectomy, success criterion A is similar to the one used in the Tube Versus Trabeculectomy trial (TVT) (IOP ≤21 mm Hg and ≥20% reduction), except for the requirement of both IOP level and percentage reduction, instead of either one. In the TVT, in which subjects had prior trabeculectomy or cataract surgery, the success rate for trabeculectomy was 69.3% at 3 years.


Success rates were reported as 62% (95% CI, 56%-68%) using criterion A and 22% (95% CI, 16%-29%) using criterion B. The success rates for criteria C and D were 72% and 23%. Despite statistically significant lowering of mean IOP and mean number of medications at 24 months, the conclusions in the paper state, “This surgery is appropriate for patients requiring a target IOP of 21 mm Hg or above.” Based on their success in criteria A and C, we suggest the statement should be: This surgery is appropriate for patients requiring a target IOP of 21 mm Hg or below.


Trabectome surgery usually lowers IOP into the mid to upper teens while reducing medication requirements, with few complications. In our view, the results reported in the target article are good, consistent with recent reports, and should not serve to discourage Trabectome use. Reducing IOP to mid to upper teens in glaucomatous eyes should decrease the rate of injury and, in some, stop ongoing damage. We believe the results of the study by Ahuja and associates support Trabectome’s use for reduction of IOP and need for glaucoma medications in eyes with mild to moderate glaucoma. Their recommendation to limit Trabectome use based on an arbitrary target IOP is unfair to patients. A recent review of minimally invasive glaucoma surgeries noted the experience base of documented Trabectome outcomes is orders of magnitude larger and equivalent to others.

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Jan 8, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Clinical Results of Ab Interno Trabeculotomy Using the Trabectome for Open-Angle Glaucoma: The Mayo Clinic Series in Rochester, Minnesota
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