Review and meta-analysis of ab-interno trabeculectomy outcomes

We analysed all of the PubMed publications on ab-interno trabeculectomy (AIT) with the Trabectome (Neomedix, Irvine, California, USA) to determine the reduction in intraocular pressure (IOP) and medications following the procedure. For IOP outcomes, PubMed was searched for 'trabectome', 'ab interno trabeculotomy' and 'ab interno trabeculectomy' and all available papers retrieved. The meta-analysis used a random-effects model to achieve conservative estimates and assess statistical heterogeneity. To investigate complications, we included all abstracts from the American Glaucoma Society, American Academy of Ophthalmology, American Society of Cataract and Refractive Surgery and the Association for Research in Vision and Ophthalmology. The overall arithmetic mean baseline IOP for standalone Trabectome was 26.71±1.34 mm Hg and decreased by 10.5±1.9 mm Hg (39% decrease) on 0.99±0.54 fewer medications. Defining success as IOP ≤21 with a 20% decrease while avoiding reoperation, the overall average success rate after 2 years was 46±34%. For combined phacoemulsification-Trabectome, the baseline IOP of 21±1.31 mm Hg decreased by 6.24±1.98 mm Hg (27% decrease) on 0.76±0.35 fewer medications. The success rate using the same definition at 2 years was 85±7%. The weighted mean IOP difference from baseline to study endpoint was 9.77 mm Hg (95% CI 8.90 to 10.64) standalone and 6.04 mm Hg (95% CI 4.95 to 7.13) for combined cases. Despite heterogeneity, meta-analysis showed significant and consistent decrease in IOP and medications from baseline to end point in AIT and phaco-AIT. The rate of visually threatening complications was <1%. On average, trabectome lowers the IOP by approximately 31% to a final IOP near 15 mm Hg while decreasing the number of medications by less than one, with a low rate of serious complications. After 2 years, the overall average success rate is 66%.