Ab Interno Trabeculotomy: Key Prognostic Factors

Abstract

Précis: 

The preoperative factors associated with a decreased survival rate of ab interno trabeculotomy (AbIT) perfomed using a Trabectome in open-angle glaucoma were selective laser trabeculoplasty (SLT) performed previously and axial length (AL) over 23.82 mm.

Purpose: 

The purpose of this study was to find preoperative factors that predict outcomes of AbIT by a Trabectome.

Materials and Methods: 

This retrospective single-center cohort study involved consecutive patients with primary open-angle glaucoma and exfoliation glaucoma treated at Helsinki University Hospital with AbIT with preoperative intraocular pressure (IOP) ≥18 mm Hg and follow-up of at least 1 year. Success was defined as lowering of their IOP by at least 20% from baseline or reduction in glaucoma medications without any rise in IOP above baseline, and no subsequent glaucoma surgery.

Results: 

Of the total 72 eyes of 67 patients, 51 eyes had exfoliation glaucoma and 21 had primary open-angle glaucoma. Mean preoperative IOP was 25.2±5.3 mm Hg, with a mean of 3.2±1.2 glaucoma medications. In the multivariable model, a history of preoperative SLT and higher preoperative AL had hazard ratios of 2.99 [95% confidence interval (CI): 1.26-7.10] and 1.53 (95% CI: 1.12-2.09) with statistical significance (P=0.013 and 0.007). The statistically significant cutoff point was 23.82 mm in AL in relation to the success rate, with success times taken into account (P<0.001). AL over 23.82 mm had hazard ratio of 5.75 (95% CI: 2.57-12.87, P<0.001).

Conclusion: 

Previous SLT and AL over 23.82 mm reduce survival after AbIT.