iStent inject as a reasonable alternative procedure following failed trabeculectomy?

The aim of this study is to assess the intraocular pressure lowering effect and the performance of the glaucoma therapy of the iStent inject in glaucoma patients with uncontrolled intraocular pressure after failed trabeculectomy.

In this retrospective study, iStent inject implantation (Glaukos Corporation, Laguna Hills, CA, USA) was performed in 22 eyes of 21 subjects suffering from glaucoma (n = 18 primary open angle glaucoma, n = 3 pseudoexfoliation glaucoma, and n = 1 for secondary glaucoma) with an intraocular pressure above target pressure after failed trabeculectomy (mean = 9.6 ± 8.1 years; range: 1-35 years). The intraocular pressure and the number of antiglaucomatous medication were assessed preoperatively, 1 day, 6 weeks, 3 months, 6 months, and 1 year after surgery and compared to preoperative findings (SPSS v23.0; Shapiro-Wilk test, Wilcoxon test, Friedman test).

The results showed a significant intraocular pressure decrease from 22.5 ± 4.6 to 15.5 ± 3.4 mmHg after 1 year follow-up (p = 0.012). The glaucoma therapy was 2.6 ± 1.2 preoperatively and reduced to 2.25 ± 1.5 number of medications after 1 year (p > 0.05). There was no significant difference in the number of medication during the whole follow-up period (1 year, p = 0.012). No significant intra- or postoperative complications were reported.

Minimal invasive glaucoma surgery (iStent inject) can offer an effective intraocular pressure reduction in advanced adult primary and secondary open angle glaucoma after failed trabeculectomy in a follow-up period of 1 year. Glaucoma therapy, however, needs to be maintained to achieve an individual target pressure and to prevent glaucoma progression. In addition, a failure rate of 27.3% makes it necessary to select carefully patients for this treatment option.