Spatial corneal endothelial cell loss after preserflo microshunt implantation: association with tube insertion position.

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.