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

ABSTRACT

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 < 200 µm, 201-500 µm, > 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 < 200 µm group vs. 1% 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 < 0.01). From month 6, tubes located > 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.