Abstract
Purpose :
There is great interest in the use of minimally invasive glaucoma surgeries, such as the Xen gel stent, to control intraocular pressure (IOP) and reduce the need for medication in patients with primary open angle glaucoma. We examined patients over a period of two years following Xen gel stent implantation to test the hypothesis that Xen is effective at lowering IOP long term.
Methods :
A retrospective study was performed on 93 eyes that had received the Xen gel stent implanted into the sub tenon space superiorly at 12:00. The sub tenon space was treated with a sponge soaked in 0.4 milligrams of mitomycin C for 45 seconds of contact. Of the eyes operated on, 16 (17.20%) failed, as defined by IOP above target or the patient being on more medications than they were able to use comfortably, and required a repeat Xen. To eliminate the confounding effect of a second Xen, only the remaining 77 eyes (82.80%) were considered. These represented 51 subjects, including 28 males and 23 females, with a mean age of 72.41. Of these 77 eyes, 58 reached 6 months post op, 34 12 months post op, and 11 24 months post op. IOP and number of IOP-lowering medications were recorded before surgery, as well as 6, 12, and 24 months post op. At each interval, IOP was compared to pre-op values using two-sample t-tests.
Results :
Prior to surgery, subjects displayed a mean IOP of 18.7±6.8 and were using a mean of 3.03±1.25 medications. 6 months after surgery, subjects had a mean IOP of 13.60±3.78 (statistically significant, p=3.17x10-6) and were on a mean of 0.36±0.74 medications. At 12 months post op, subjects had a mean IOP of 13.24±3.0 (statistically significant, p=1.23x10-6) with a mean of 0.41±0.81 medications. 24 months after surgery, subjects had a mean IOP of 13.72±2.26 (statistically significant, p=1.41x10-4). Subjects displayed a mean of 1.00±1.21 medications at this time, while the median and mode remained at 0 medications for all three intervals.
Conclusions :
These data support the hypothesis that Xen gel stent implantation offers statistically significant reduction in IOP over an extended period of two years after surgery, as demonstrated by mean IOP in the low teens and a mean of less than 1 medication. Further research is indicated to extrapolate these results to longer periods of time. Doing so would further point to the Xen gel stent as an effective surgical option for patients with primary open angle glaucoma.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.