Efficacy of multiple Xen gel stent in treating primary open angle glaucoma

Abstract

Purpose : Multiple Xen as an alternative to trabeculectomy or tube shunts has not been reported in literature. The purpose of this study is to assess the effectiveness of multiple Xen in controlling IOP and reducing the number of medications following failure of the first Xen.

Methods : This was a retrospective study using data from eyes (n=16) who’ve undergone a 2^nd Xen gel stent procedure following the failure of the 1^st. Failure was defined as not meeting target IOP or number of medications. The Xen was implanted into the sub tenon space superiorly at 12:00. The sub tenon space was treated with a sponge soaked in 0.4 milligram mitomycin C and held with 45 seconds of contact. Eyes were followed from baseline until 12 months. Baseline is defined as the visit prior to operation. The primary endpoint was defined as the mean IOP at 12 months with a secondary endpoint of mean number of IOP lowering medications at 12 months. To determine statistical significance, a two-tailed t-test was used.

Results : The average age was 74.50 years±9.905. Of the 16 eyes followed, the mean IOP prior to the 1^st Xen was 21.56 mmHg±5.71 with a median IOP of 18.5mmHg. The average length of success for the primary Xen was 215 days± 328.52 before failure occurred. The most common time to failure was 42 days and a median time of 107 days. Prior to 2^nd Xen implantation, mean IOP was 22.38mmHg±6.10 with a median IOP of 22.00mmHg. At 1 month, mean IOP was 13.43mmHg±6.53 (p=0.0002). 6 month follow up showed a mean IOP of 13.50mmHg±3.58 (p=0.00000716). Mean IOP stabilized at 12 months with an mmHg level of 12.00±2.3 (p=0.000000176). The mean number of medications was also analyzed at baseline to be 1.75±1.20. At 6 months post-op, mean medication was 0.70±1.10. At 12 months, the mean number of medications decreased to 0.57±0.90.

Conclusions : Our findings suggest that a second Xen implantation, after the failure of the first, effectively controlled IOP and significantly reduced the number of IOP-lowering medications required. The early occurrence of failure with the primary Xen underscores the need for prompt intervention, and our results demonstrate that the second Xen procedure led to a substantial and sustained reduction in IOP over the 12-month follow-up period. Notably, the mean number of medications also exhibited a significant decline, indicating the potential for enhanced patient outcomes and reduced medication burden.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.