Corneal Tissue Addition Keratoplasty for the Treatment of Keratoconus: A Review.

Keratoconus, characterized by loss of corneal structural integrity causing stromal thinning, has both surgical and nonsurgical management options. While corneal cross-linking is being increasingly used to halt the progression of keratoconus, it is reserved for patients with milder disease and thicker corneas. Tissue addition keratoplasty has recently emerged as a treatment option for patients with more advanced keratoconus. Studies of available tissue addition keratoplasty techniques, including Bowman layer transplantation, corneal allogenic intrastromal ring segments, and intralamellar keratoplasty, show flattening of corneal keratometry and improved visual outcomes, with increased rates of contact lens fitting. The purpose of this review is to discuss available options regarding tissue addition keratoplasty.