2020–2021 BCSC Basic and Clinical Science Course™
13 Refractive Surgery
Chapter 5: Photoablation: Techniques and Outcomes
Excimer Laser
Surface Ablation
Surface ablation procedures were initially performed as PRK, the sculpting of the de-epithelialized corneal stroma to alter refractive power, and they underwent extensive preclinical investigation before being applied to sighted human eyes. Results of early animal studies provided evidence of relatively normal wound healing in laser-ablated corneas.
The popularity of PRK decreased in the late 1990s when LASIK began to be performed because of LASIK’s faster recovery of vision and decreased postoperative discomfort. Although more LASIK than surface ablation procedures are still performed, the number of surface ablations has increased in recent years. PRK remains an especially attractive alternative for specific indications, including irregular or thin corneas; epithelial basement membrane disease (often called map-dot-fingerprint dystrophy); previous corneal surgery, such as penetrating keratoplasty (PKP) and radial keratotomy (RK); and treatment of some LASIK flap complications, such as incomplete or buttonholed flaps. Surface ablation eliminates the potential for stromal flap–related complications and may have a decreased incidence of postoperative dry eye as compared to LASIK. Corneal haze, the major risk of PRK, decreased markedly with the use of adjunctive mitomycin C; subsequently, the use of PRK for higher levels of myopia has increased.
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Majmudar PA, Forstot SL, Dennis RF, et al. Topical mitomycin-C for subepithelial fibrosis after refractive corneal surgery. Ophthalmology. 2000;107(1):89–94.
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Srinivasan R. Ablation of polymers and biological tissue by ultraviolet lasers. Science. 1986; 234(4776):559–565.
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Trokel SL, Srinivasan R, Braren B. Excimer laser surgery of the cornea. Am J Ophthalmol. 1983; 96(6):710–715.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.