Vitality of epithelial cells after alcohol exposure during laser-assisted subepithelial keratectomy flap preparation

Abstract

Exposure to 20% ethanol should be 20 to 30 seconds as the number of vital epithelial cells rapidly decreased after that. Vitality of the epithelial flap is probably a crucial factor in the dampened wound response in LASEK compared to that in photorefractive keratectomy.

A Randomized Prospective Clinical Trial Comparing Laser SubepithelialKeratomileusis and Photorefractive Keratectomy

“…Recent studies 2,5,9,11,12 have shown a reduction in pain, faster visual rehabilitation, better visual acuity, and decreased corneal haze in LASEK-treated patients compared with PRK-treated patients; thus, LASEK has been proposed to be a superior refractive procedure compared with PRK. Another study 10 has also shown the vitality of corneal epithelial cells after exposure to the diluted alcohol. Photorefractive keratectomy, on the other hand, has been well established for the past decade to be the standard traditional method of treating myopia, hypermetropia, and certain types of astigmatism.…”

“…[7][8][9] In LASEK, a corneal epithelial flap is created using diluted alcohol (18%-20%) placed on the cornea for 30 to 40 seconds. 10 Thereafter, the same excimer laser used typically for PRK or laser in situ keratomileusis is used to ablate the corneal stroma. 1 The epithelial flap is reflected back on the cornea at the end of the LASEK procedure.…”

Outcomes of Epi-LASIK for the Correction of High Myopia and Myopic Astigmatism after More than 1 Year

“…The idea of LASEK has evolved from PRK after alcohol-assisted epithelium removal to maintain an epithelial flap that can be repositioned on the laser-ablated corneal surface. Although LASEK may provide advantages over PRK for the correction of myopia, the probable toxic effect of alcohol on the epithelium and haze are of concern, especially in high myopia [5,6,7]. In 2003, Pallikaris et al [9, 19] reported on epi-LASIK, and the fundamental difference between the epi-LASIK and LASEK is that the separation of the epithelial sheet is obtained mechanically without the need for chemical treatment of the epithelium.…”

“…Pallikaris et al [4] developed epi-LASIK and epikeratome as an alternative method for separating corneal epithelial before surface ablation. The fundamental difference from LASEK is that the separation of the epithelial sheet is obtained mechanically, which not only decreases alcohol-related complications, but also provides a rather automated surgical procedure with a short learning curve for an experienced refractive surgeon [5,6,7,8]. …”

Epi-laser in situ keratomileusis: Comparative evaluation of epithelial separation with 3 microkeratomes

“…10 In contrast to LASEK, which was first described by Camellin in 1999, the epithelial flap in epi-LASIK surgery is created with the help of a microkeratome without using alcohol (M. Cimberle, ''LASEK May Offer the Advantages of Both LASIK and PRK,'' Ocular Surgery News, International Edition, March 1999; pages [14][15]. Therefore, the potential toxic effect of alcohol [11][12][13] is avoided. Due to the automated process, epi-LASIK is easier to perform than LASEK for inexperienced surgeons.…”