New surgical technique shows promise for advanced keratoconus

This small case series found that mid-stromal implantation of a Bowman layer graft reduced ectasia in eyes with advanced keratoconus. 

The authors speculate that Bowman layer fragmentation is a feature of advanced keratoconus. They say that transplantion of a Bowman layer graft may serve to flatten the corneal curvature via the transplanted Bowman layer acting as an elastic splint and through the wound-healing reaction between donor and host. 

They performed mid-stromal dissection with implantation of an isolated donor Bowman layer graft in the stromal pocket in 10 eyes of 9 patients with advanced keratoconus with contact lens intolerance but no corneal scarring.

With this technique, keratometry values decreased by a mean of 6.2 D (74.5 D preoperatively to 68.3 D postoperatively, P = 0.002). After surgery, all eyes were able to be fitted with a scleral-supported rigid contact lens.

All surgical procedures were uneventful, and throughout the 24-month study period the researchers observed no complications related to stromal dissection and/or implantation of the Bowman layer graft.

In keratoconic eyes that are not candidates for UV-A crosslinking (i.e., stroma less than 400 microns and keratometry values > 58D) and whose only option is PK or DALK, this technique may be a safe, viable alternative for visual rehabilitation and returning to wearing contact lenses.