Abstract
Purpose To achieve a highly balanced comparison of trabecular bypass stenting (IS2, iStent inject) with ab interno trabeculectomy (T, Trabectome) by exact matching.
Methods Fifty-three IS2 eyes were matched to 3446 T eyes. Patients were matched using exact matching by baseline intraocular pressure (IOP), the number of glaucoma medications, and glaucoma type, and using nearest neighbor matching by age. Individuals without a close match were excluded. All surgeries were combined with phacoemulsification.
Results A total of 78 eyes (39 in each group) could be matched as exact pairs with a baseline IOP of 18.3 +/- 5.1 mmHg and glaucoma medications of 2.7 +/- 1.2 in each. IOP in IS2 was reduced to 14.6 +/- 4.2 mmHg at 3 months and in T to a minimum of 13.1 +/- 3.2 mmHg at 1 month. In IS2, IOP began to rise again at 6 months, eventually exceeding baseline. At 24 months, IOP in IS2 was 18.8 +/- 9.0 mmHg and in T 14.2 +/- 3.5 mmHg. IS2 had a higher average IOP than T at all postoperative visits (p< 0.05 at 1, 12, 18 months). Glaucoma medications decreased to 2.0 +/- 1.5 in IS2 and to 1.5 +/- 1.4 in T.
Conclusion T resulted in a larger and sustained IOP reduction compared with IS2 where a rebound occurred after 6 months to slightly above preoperative values.