Methods
cataract, open-angle glaucoma, interno
CATARACT, OPEN-ANGLE GLAUCOMA, CORNEA, SCLERA
This prospective, cross-sectional, non-randomized, monocentric clinical evaluation in a patient to treat population was conducted in a tertiary health care center. The study and data collection were carried out with approval from the appropriate institutional review board. The authors confirm that the study and data collection were conducted in conformity with all federal and state laws, informed consent was obtained, and the study was in adherence to the tenets of the Declaration of Helsinki. Clinical trial registration information is publicly available at The study cohort consists of two groups of intention to treat patients. One hundred and fifty-five consecutive eyes received either XEN45 implants only (solo surgery group) or combined surgery/cataract surgeries were performed (combined surgery group). Only patients with insufficiently controlled IOP or intolerance to topical therapy in mild to moderate open-angle glaucoma were included in the study. The feasibility to measure endothelial cell count was mandatory. Patients with further additional IOP-lowering procedures (except needlings, bleb revisions, YAG lasers, or Argon lasers) were excluded from the analysis. Surgeries took place between 2014 and 2019. All endothelial cell counts were recorded within 3 months preoperatively at baseline visit. All 155 eyes underwent 2 study visits: a baseline visit preoperatively between the years 2014 and 2019, and a last postoperative visit in the year 2021. Patients could choose to have corneal endothelial cell follow-ups yearly in between at the study center, but this was not obligatory. Of the eyes, 37% (58/155) used the offer of interim visits a minimum of once. As far as available, interim data between the XEN45 surgery date and the date of the last postoperative visit in 2021 were also included in the data analysis.The primary endpoint was the change in central endothelial cell density at the last postoperative visit in comparison to preoperative data.XEN45 surgeries were performed in accordance with our previously published XEN45 treatment algorithm [XEN45 gel stents were implanted ab interno after intra-tenon application of mitomycin C (0.05–0.2 ml, 4–16 μg MMC total).In the solo surgery group, XEN45 was implanted in the superior-nasal quadrant via a 1.1-mm clear corneal inferior-temporal incision while stabilizing the eye with a second instrument (Phaco Spatula) via a 0.7-mm clear corneal superior-temporal incision. Cohesive viscoelastic (Healon GV) was used to maintain the anterior chamber depth during implantation. Gonioscopy was used intraoperatively while entering the sclera at the angle. The entry position of the XEN45 into the sclera was aimed anterior adjacent to Schlemm’s canal; the aimed length of the scleral tunnel was 2 mm with an exit point 3 mm posterior to the limbus. The remaining length of the XEN45 in the anterior chamber was adjusted to approximately 1 mm at the end of surgery. After removing the viscoelastic from the AC, an intracameral antibiotic was administered at the end of surgery (cefuroxime 0.1 ml).In the combined surgery group, clear corneal ports from cataract surgery were used for subsequent XEN45 implantation. A temporal approach was used for all cataract surgeries. The same phacoemulsification machine was used in all eyes (Oertli Faros, Oertli, Switzerland). For cataract surgery, a dispersive viscoelastic was used in all eyes (MEDIO-CLEAR 2.0%, Aivimed, Germany). Subsequent XEN45 implantation was performed as described above.Postoperatively, the patients received preservative-free topical corticosteroids for a minimum of 6 weeks (dexamethasone, minimum TID, first week Q1HTwo patient groups were analyzed separately and overall: the solo surgery group and the combined surgery group.During their last visit in 2021, patients were assessed as to endothelial cell density and the position of the XEN45 measured by anterior segment optical coherence tomography and gonioscopy. Gonioscopy and angle by Shaffer Grade were assessed in the quadrant of XEN45 implantation (superior-nasal). The position of the XEN45 was graded as follows: anterior to Schwalbe line, in Schwalbe line, anterior to Schlemm’s Canal, in Schlemm’s Canal, in the non-pigmented trabecular meshwork, in pigmented trabecular meshwork, posterior to pigmented trabecular meshwork, at scleral Spur (see Fig. Gonioscopy and assessment of the XEN45 entry in the sclera. In these examples, the XEN45 enters the sclera at the pigmented trabecular meshwork (left) and at the scleral spur (right)Anterior segment optical coherence tomography (AS-OCT, Visante OCT, Zeiss; Fig. Parameters assessed by anterior segment OCT. Radial AS-OCT section showing the XEN45 stent with (Using a Konan CellChek XL Specular Microscope (Konan Medical), endothelial cell densities were measured at 3 positions: central, superior-nasal (location of XEN45 implantation), and inferior-temporal (opposite the XEN45 implant).Central corneal thickness was measured in the center of the cornea (Pocket II Pachymeter, Quantel Medical, France).The same devices were used pre- and postoperatively for measurements of endothelial cell density and central corneal thickness.Slit lamp and dilated fundus examinations were performed per clinical routine.