Bowman layer transplantation: 5-year results.

Abstract

The purpose of this study was to evaluate the 5-year clinical results of isolated Bowman layer (BL) transplantation in the treatment of advanced keratoconus. In this prospective, single-center, interventional case series at a tertiary referral center, 20 eyes of 17 patients with advanced keratoconus underwent BL transplantation, i.e. an isolated Bowman layer graft was positioned into a manually dissected mid-stromal pocket. Scheimpflug-based corneal tomography measurements, best corrected spectacle and contact lens visual acuities (BSCVA and BCLVA), endothelial cell density, and complications were evaluated up to 5years after surgery. Measured simulated and maximum keratometry (Kmean and Kmax) values were stable up to 5years after surgery (P = .310 and P = .195 for 5years compared to 1month follow-up, respectively), following an initial decrease from pre- to 1month postoperatively (P < .001 each). Mean LogMAR BSCVA remained stable (P > .99), after an initial improvement from pre- to 12months postoperatively (P = .007). Mean BCLVA did not change from preoperative to 5years postoperatively (P = .219). During all postoperative follow-ups, mean densitometry values were higher than preoperatively (P < .001). A corneal hydrops occurred in one eye at 4.5years postoperatively; no other postoperative complications were observed. Kaplan-Meier analysis showed an estimated success rate of 84% at 5years postoperatively. Endothelial cell density remained stable from before to 5years after surgery (P = .319). After early postoperative corneal flattening, topographies were stable up to 5years after BL transplantation, preserving BCLVA and contact lens tolerance, potentially allowing long term postponement of penetrating or deep anterior lamellar keratoplasty.