Abstract
Purpose :
To compare small incision sub-Tenon ab interno Xen implantation with iStent, Trabeculectomy, and Ahmed tube shunt visual acuity (VA) changes and efficacy in treating primary open angle glaucoma.
Methods :
Xen was implanted by a single surgeon using small incision sub-Tenon ab interno technique. 11 eyes from the start of 2020 until September 28th, 2021, were recorded. Each subject had their VA checked via computer Snellen chart, intraocular pressure (IOP) by applanation tonometer, silt lamp exam was performed to determine bleb avascularity, and glaucoma medications were checked at each visit. Data was taken from pre-implantation, 1-day post-implantation, and 6 months post-implantation. T-Test was performed for statistical significance. IStent, Ahmed tube shunt, and trabeculectomy data were compiled from previous studies
Results :
The average age of subjects receiving Xen was 70 ± 10.79. Mean IOP at 6 months was 13.17 ± 1.64 (p=0.003, 12-17), median IOP was 12.5. Of these, 100% of subjects had IOP of 17 or below, 91% were 15 or below, and 55% of 12 or below. IStent mean IOP at 6 months was 15.8 ± 3.0 (p<0.001). Ahmed tube shunt had a mean IOP at 6 months of 12± 4.6 (p<0.001). Trabeculectomy IOP at 6 months was 13.4 ± 4.2 (p<0.001, 6-32) No eyes receiving Xen developed an avascular bleb due to the procedure.
Xen mean decrease of medications was 1.58 ± 1.31 at 6 months. IStent mean decrease in medications was 1 ± 0.8 (p<0.001). Ahmed tube shunt mean number of medications went from 2.97 ± 2.03 to 1.05 ± 1.15. Trabeculectomy medications went from 3.6 ± 0.9 (1-5) to 0.37 ± 0.9 (0-4).
Xen mean VA recovery time to return to normal was 1 week. IStent VA is neutral following surgery. Ahmed tube shunt worst VA occurred at 1 week postoperatively and mean VA returned to preoperative levels by 3 months. Trabeculectomy mean VA returned to preoperative levels in 88 days (6-720 days).
Conclusions :
Xen had a lower IOP at 6 months than iStent with a similar decrease in medications, while mean visual acuity returned to baseline one week after. Xen had similar IOP at 6 months with Ahmed tube shunt and trabeculectomy, similar decrease in medications with Ahmed tube shunt, and faster return to preoperative VA. Since no eyes receiving Xen developed an avascular bleb, the tissue is still viable for possible additional procedures.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.