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Spatial corneal endothelial cell loss after preserflo microshunt implantation: association with tube insertion
Mitsuya Otsuka1, Akio Miyakoshi2, Yasuhito Nitta2
1Department of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan. otsuka@med.u-toyama.ac.jp.
Purpose:
To investigate spatial corneal endothelial cell density (ECD) changes after PreserFlo MicroShunt™ (PFM) implantation and identify tube-related factors associated with localized endothelial cell loss.
Study Design:
Retrospective clinical study.
Methods:
This study included 118 eyes of 118 patients with medically refractory glaucoma who underwent PFM implantation and were followed for ≥6 months. Anterior-segment optical coherence tomography was used to evaluate tube-cornea distance, tube-cornea angle, and intracameral tube length. Gonioscopic images obtained 1 month postoperatively were used to classify tube insertion as iris-side, trabecular, or corneal-side. ECD was measured at nine corneal regions using specular microscopy. The primary outcome was the ECD reduction rate at the tube insertion site (Position 3) at 3 and 6 months. Linear mixed-effects models were used to identify factors associated with localized endothelial cell loss.
Results:
Tube insertion locations were iris-side in 36 eyes, trabecular in 73 eyes, and corneal-side in 9 eyes. In the primary linear mixed-effects analysis, compared with iris-side insertion, both trabecular-contact insertion (β = 12.8%, P = 0.026) and corneal-side insertion (β = 28.6%, P = 0.007) were associated with greater localized endothelial cell loss after multivariable adjustment. Central ECD reduction was mild (2.1% at 6 months).
Conclusions:
Early localized endothelial cell loss after PFM implantation was associated with tube insertion position, particularly corneal-side insertion. Central ECD measurements may underestimate localized endothelial cell loss.
