A multi-centre interventional case series of 259 ab-interno Xen gel implants for glaucoma, with and without combined cataract surgery

Aims To assess the efficacy of Xen in reducing intraocular pressure (IOP) in varying glaucoma subtypes. To assess the effect of combined phacoemulsification. To determine the frequency of complications and explore further bleb management needed. Methods Retrospective case note review of all patients undergoing Xen implantation across four centres from August 2015 to May 2017. Results In total, 259 consecutive surgeries of 226 patients were reviewed. IOP reduced from 19.3 (SD ± 6.0) mmHg preoperatively to 14.2 (SD ± 4.4) at month 12 and 13.5 (SD ± 3.3) at month 18 ( p < 0.0001). Medication usage reduced from 2.6 (±1.1) preoperatively to 0.8 (±1.0) at month 12 ( p < 0.0001) and 1.1 (±1.3) medications at month 18 ( p < 0.0001). Simultaneous phacoemulsification did not alter outcomes as Xen IOP was 14.3 (SD ± 4.7) mmHg and Phaco-Xen was 13.8 (SD ± 2.6) mmHg at month 12 ( p = 0.5367). Xen appears to be effective in previous failed filtration surgery. Adverse events included: IOP spikes of ≥30 mmHg in 33 (12.7%) cases, secondary filtration surgery required in 24 (9.3%) cases; implant exposure in 6 (2.3%) cases; persistent hypotonous maculopathy in 5 (1.9%) cases; persistent choroidal effusions in 4 (1.5%) cases; a cyclodialysis cleft secondary to implant insertion in 1 (0.5%) case; and 1 (0.5%) case of endophthalmitis post-implant bleb resuturing. In all, 40.9% of cases required postoperative bleb needling or antimetabolite injection. Conclusions Xen reduces IOP and medications at 18 months. Adverse events are uncommon. Careful postoperative surveillance and low threshold for bleb management is needed. Xen is safe and effective in mild to moderate glaucoma.