One-year outcomes of an ab externo sibs microshunt in combination with phacoemulsification

To evaluate the intraocular pressure (IOP)-lowering effect, adverse event profile, and risk factors for failure of an ab externo microshunt combined with phacoemulsification after 1 year of follow-up.

A retrospective, single-center, interventional cohort study.

One hundred nineteen consecutive glaucomatous eyes of 97 patients with an IOP above target or progressing on maximal medical therapy.

All eyes underwent ab externo microshunt surgery with mitomycin C in combination with phacoemulsification from July 2015 to June 2019.

Primary outcome was complete success, defined as (1) no 2 consecutive IOP readings >17 mm Hg or IOP <6 mm Hg with >2 lines of vision loss, (2) at least 20% IOP reduction from baseline, and (3) on no medications. Secondary outcomes included upper IOP thresholds of 14 mm Hg and 21 mm Hg, qualified success (with medications), change in IOP, medications, visual outcomes, complications, interventions, and reoperations.

At 1-year, complete success was achieved in 67.5% of eyes and qualified success in 79.8%. The median best-corrected vision acuity improved from 0.4 (interquartile range [IQR] 0.2-0.7) at baseline to 0.14 (IQR 0.1-0.3) at 1 year (p < 0.0001), with 93.2% having the same or improved vision. The most common complications were shallow anterior chamber (10.1%), iritis (9.2%), and choroidal detachment (8.4%). Needling was required in 24.4% of the eyes. Reoperation was required in 5.9% of the eyes.

The ab externo SIBS microshunt demonstrates reasonable rates of complete and qualified success at 1 year, decreased IOP and medication use, good visual outcomes, and few reoperations when performed in combination with phacoemulsification.