Photodynamic biologic tissue glue to enhance corneal wound healing after radial keratotomy

Abstract

Purpose: To evaluate the effect of photodynamic biologic tissue glue (PBTG) on corneal wound healing after radial keratotomy (RK).Setting: Cornea Research Laboratory, The University of Chicago, Chicago, Illinois, USA.Methods: Bidirectional, eight-incision RK was done in one eye of eight Dutch pigmented rabbits. Then, PBTG was inserted into the RK incisions and activated with an argon blue-green laser in four treatment eyes. The rabbits were divided into three groups: early, in which corneal wound healing was assessed at 1 and 3 weeks; late, in which corneal wound healing was assessed at 8 weeks; enhancement.Results: The PBTG-treated keratotomy wounds had a more prominent epithelial healing response immediately after RK and a decreased propensity for wound dehiscence. Collagen fiber arrangement in the PBTG-treated incisions was sagittal to the keratotomy wound 1 to 3 weeks after RK and then changed to a transverse orientation across the keratotomy wound by 8 weeks. The control keratotomy wounds had a less prominent epithelial healing response and developed late disorganization of the posterior keratotomy wound at 8 weeks. Keratometry measurements 2 months after RK showed corneal flattening of 1.0 diopter (D) in the PBTG-treated eye and 6.5 D in the control eye, which is consistent with histologic studies showing more advanced wound healing in the PBTG-treated eyes. After RK enhancement, the PBTG-treated eye resisted further corneal flattening and had 4.5 D of corneal steepening; the control eye had 2.0 D of additional corneal flattening.Conclusion: The nontoxic, laser-activated adhesive PBTG accelerated corneal wound healing after RK and simulated the placement of sutures into the RK wound. Thus, PBTG may be an alternative to sutures to correct hyperopia after RK in humans.