Corneal Endothelial Cell Loss After PRESERFLO™ MicroShunt Implantation in the Anterior Chamber: Anterior Segment OCT Tube Location as a Risk Factor

Introduction To analyze the effects of PRESERFLO on corneal endothelial cell density (ECD). Methods Forty-six eyes that underwent PRESERFLO implantation were followed up for 12 months. Specular microscopy was performed preoperatively and at 1, 3, 6, and 12 months postoperatively to measure central ECD and mean monthly reduction (MMR). Anterior segment optical coherence tomography (AS-OCT) was applied to measure the tube–endothelium (TE 500 μm) distance. The relationship between TE distance and ECD was analyzed with a linear mixed-effects model. Results Central ECD decreased significantly at 1 year (7.4%, p = 0.04), with an MMR of −15 ± 25 cells/mm2. Regarding TE distance groups, there was an 18% ECD reduction in the 500 μm group (p = 0.08). Endothelial cell loss was related to TE distance (mean 482.9 ± 238 μm), with a higher rate at 1 month in comparison to 12 months for the same tube position in the anterior chamber (−174.8 ± 65.2 cells/mm2 at 1 month vs. 30.2 ± 11.3 cells/mm2 at 12 months, p 600 μm from the endothelium showed EC loss close to zero. Conclusions The PRESERFLO implant is associated with a loss of EC from the immediate postoperative period that continues over time at lower rates. A shorter TE distance appears to cause more severe ECD loss.