Refractive Surgery After Corneal Transplantation

Abstract

SUMMARY A lthough being the most successful organ transplantation, keratoplasty is usually followed by significant ametropia. A clear corneal graft is no longer considered a success if it is associated with significant degrees of refractive errors. Astigmatism, both regular and irregular, is the most common cause of suboptimal vision after keratoplasty. Patients who have failed optical correction of post-keratoplasty refractive errors should be considered as candidates for surgical refractive intervention. There are different surgical options to address residual refractive errors that frequently occur after corneal transplantation. None of them appear as a perfect option and corneal surgeons should tailor a specific plan for each patient individually. Many factors affect the surgeon's choice of the best surgical option including the ocular condition, patient requirements, surgeon skills and the available technology. The ocular condition as well as the type of refractive error and its degree remain the most important factors in the choice of the refractive intervention. The correction can be done on the corneal surface or intraocularly using intraocular lens (IOL) implantation both of which require complete tectonic and refractive stability after suture removal. Corneal procedures are favorable for relatively lower errors, whereas intraocular procedures are favorable for higher ones. The most commonly used procedures are photorefractive keratectomy, laser in-situ keratomileusis, astigmatic keratotomies and phakic IOLs. The graft surface regularity is influential. Low regular astigmatism can be corrected with femtosecond laser-assisted astigmatic keratotomies, whereas irregular astigmatism necessitates customized laser ablation. If the choice is for corneal procedure, the cornea is carefully evaluated to choose between LASIK and PRK. LASIK is used in grafts with adequate thickness and provides faster visual recovery with lesser corneal haze when compared to PRK. However, it carries higher risk of flap-related complications and graft-host junction dehiscence. On the other hand, PRK can be used in thinner superficially opaque grafts but is associated with increased risk of postoperative haze and regression. If the choice is for phakic IOL implantation, the type can be determined according to endothelial cell count and ant