Effects of Ab Interno XEN Gel Implantation on Postural Intraocular Pressure Elevations

Purpose: The aim of this study was to analyze the postural intraocular pressure (IOP) changes in open-angle glaucoma after ab interno XEN gel implant surgery and to compare them with the changes observed with trabeculectomy and medical treatment.Patients and Methods: The study sample included 18 patients with XEN gel implants, 30 patients who had trabeculectomy, and 30 medically managed glaucoma patients. All patients in XEN gel implant and trabeculectomy groups had at least 11 months of follow-up and had successful surgeries that resulted in medication-free control of IOP. A rebound tonometer (Icare, Finland Oy, Helsinki, Finland) was used to measure the IOP levels at the sitting, supine, and dependent lateral decubitus (DLDP) positions after a 5-minute rest at each position.Results: In all the groups, the mean IOP values in the DLDP and supine positions were significantly higher than the sitting position. The IOP elevation after moving from sitting to supine position was significantly reduced in XEN gel implant and trabeculectomy groups compared to medical treatment group (p = .001 and p = .002, respectively). The IOP elevation after a moving from sitting to DLDP was also significantly reduced in XEN gel implant and trabeculectomy groups compared to the medical treatment group (p = .003 and p = .01, respectively). However, there was no significant difference in IOP change after moving from sitting to supine or DLDP positions between XEN gel implant and trabeculectomy groups (p = .74 and p = .98, respectively).Conclusion: This study demonstrated that XEN gel implant could reduce postural elevations in IOP to the same degree as trabeculectomy and provide significantly better postural IOP control than medical treatment. This surgery can be an effective minimally invasive alternative for patients with significant positional IOP elevations.