Corneal ectasia after photorefractive keratectomy

Abstract

PRK induced corneal ectasia in predisposed eyes, even after low myopic ablations. Forme fruste keratoconus and keratoconus in the fellow eye were the main pre-operative findings. Prognosis varies according to severity.

Refractive surgery for keratoconus

“…Risk factors associated with keratectasia include thin pre-operative corneas, treatment of high myopia, thin residual stromal beds, preoperative topographic changes of keratoconus or forme fruste keratoconus in the affected or contralateral eye or a family history of keratoconus. [7][8][9][10] The exact pathogenesis of keratectasia post-excimer laser refractive surgery is not clear but it is believed that the thinning and the biochemical stress induced by laser surgery trigger further biomechanical weakening of a pathologic cornea. Debate surrounds whether the actual process of ectasia in these cases is exactly the same as keratoconus or whether it differs.…”

High-irradiance CXL combined with myopic LASIK: flap and residual stroma biomechanical properties studied ex-vivo

“…There are two main reasons that we target to avoid any cross-linking effect on the flap. First is that the flap does not contribute to the biomechanical properties of the underlying stroma 37 38. Therefore, there is no benefit from a potential cross-linking of the flap.…”

Collagen Corneal Cross-Linking followed by Intac Implantation in a Case of Post-PRK Ectasia

“…Similar results were attained in cases of CXL treatment for post-LASIK ectasia. 3,4 Post-photorefractive keratectomy (PRK) ectasia, a rare PRK complication, has been reported in only a few cases, [5][6][7][8] despite the fact that PRK is the oldest form of laser refractive surgery.…”