Novel methods to maintain corneal transparency while increasing the strength of LASIK flaps

Purpose To reduce the incidents of keratectasia after LASIK we have been attempting to increase the strength of the flap using various methods1. We now are aiming to improve this by transplanting stromal fibroblasts, oral fibroblasts (a scarless reparative cell type) or stromal progenitor cells into LASIK corneas. Methods LASIK flaps were created in ovine corneas and human oral fibroblasts or human stromal progenitor cells were applied on the flap bed. Stromal flaps in bovine corneas were treated with stromal fibroblasts from the same species. LASIK corneas without any treatment acted as controls. All samples were placed in organ culture and allowed to heal for up to 3 weeks. The mechanical strength of the flaps was measured using a vertical extensometer in a “pull to break” test. Transparency was assessed by making spectorphotometric measurements across the visible spectrum. Cell phenotype was examined by anti-alpha smooth muscle actin immunostaining. Results All approaches improved the strength of LASIK flaps but the bovine stromal fibroblasts compromised the tissue’s transparency. Both human cell types maintained corneal transparency but the oral fibroblast approach was the most efficient one in the 3 week culture period, perhaps due to the scarless reparative phenotype of these cells. Conclusion LASIK flap strength can be increased biologically but the challenge now is to apply these methods in an animal model to assess the long term of the efficacy of increasing flap adhesion strength and maintain corneal transparency and its potential use in medical intervention. 1. Mi S, Dooley EP, Albon J, Boulton ME, Meek KM, Kamma-Lorger CS. J Cataract Refract Surg. 2011; 37(1):166-72