Evaluating the outcomes of inferonasal ahmed valve implantation using the double scleral tunnel technique in refractory glaucoma.

BACKGROUND

To evaluate the efficacy and safety of inferonasal quadrant (IN) Ahmed Valve implantation (AVI) using the double scleral tunnel technique in patients who had previously failed glaucoma surgery.

METHODS

This retrospective comparative study included data from 69 patients diagnosed with refractory glaucoma who were followed in a tertiary referral hospital. The IN-AVI group included 35 patients who underwent IN-AVI after failed trabeculectomy or superotemporal quadrant (ST) AVI, and the ST-AVI group included 34 patients who underwent primary ST-AVI. The primary outcome was to analyse the surgical success rate, the secondary outcome was to compare the intraocular pressure (IOP) reduction in the IN-AVI and ST-AVI groups at 1-year postoperatively.

RESULTS

Significant reduction in IOP was observed after IN-AVI at 1-year postoperatively (p < 0.001). The overall success rate was 88.6%. IN-AVI after failed trabeculectomy didn't differ from primary ST-AVI in terms of IOP reduction. IN-AVI after failed ST-AVI showed a lower IOP reduction compared to primary ST-AVI (p = 0.003). No tube exposure was observed at 1-year postoperatively using the double scleral tunnel technique.

CONCLUSIONS

In patients with refractory glaucoma, IN-AVI after failed trabeculectomy was as effective as the primary ST-AVI. Although IN-AVI after failed ST-AVI was effective in reducing IOP, it was significantly less effective than the primary ST-AVI. The prior failure of a trabeculectomy had no impact on the success of AVI. Conversely, a second AVI was less efficacious than the primary AVI.