Association between distance from the angle recess to the tube entry site and corneal endothelial cell loss after PreserFlo MicroShunt implantation

Abstract Purpose To investigate the association between anterior segment optical coherence tomography (AS-OCT)–derived tube parameters and corneal endothelial cell density (ECD) changes after PreserFlo MicroShunt (PMS) surgery in primary open-angle glaucoma (POAG) and exfoliation glaucoma (XFG). Study design Prospective cohort study. Methods This study included pseudophakic patients with POAG or XFG who underwent PMS implantation. ECD was measured preoperatively and at 1, 3, 6, and 12 months post operatively, and every 6 months thereafter. Intracameral tube parameters, including tube position and length, were assessed using AS-OCT images obtained 1 month postoperatively. Associations between OCT parameters and the monthly rate of ECD change (ECD slope) were evaluated using linear mixed-effects models. Results Mean preoperative ECD was 2384 ± 391 cells/mm 2 . Mean follow-up period was 15 ± 7 months, with 5.1 ± 1.3 ECD measurements per eye. Tube parameters did not differ significantly between POAG (67 eyes of 61 patients) and XFG (18 eyes of 16 patients). The mean ECD slope was −11.8 ± 2.2 cells/mm 2 /month in XFG and −9.8 ± 1.1 cells/mm 2 /month in POAG (p = 0.38). A greater distance from the angle recess to the intracameral tube entry site was significantly associated with a more negative ECD slope in both XFG and POAG groups (p = 0.02 and 0.03). Its contribution to ECD slope variance was greater in XFG than in POAG (R 2 = 0.243 vs. 0.069). Conclusion A longer distance from the angle recess to the intracameral tube entry site may predict accelerated ECD loss after PMS implantation, particularly in XFG.