Photorefractive keratectomy results in myopic patients with thin cornea eyes

• Main Authors: Hassan Hashemi, Mohammad Miraftab, Soheila Asgari
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2015-01-01
• Series: Oman Journal of Ophthalmology
• Subjects: Higher order aberrations; mesopic contrast sensitivity; photorefractive keratectomy; thin cornea
• Online Access: http://www.ojoonline.org/article.asp?issn=0974-620X;year=2015;volume=8;issue=1;spage=24;epage=27;aulast=Hashemi

Background: To evaluate the results of visual acuity and quality, and corneal integrity in myopic patients with a thin cornea who received photorefractive keratectomy (PRK). Materials and Methods: In this before-after interventional study, 30 myopic eyes with a myopia −3.76 ± 1.72 (−6.50 to −1.25) D and a corneal thickness of 486.03 ± 11.93 (452-499) μm at the thinnest point received PRK. In myopia was more than 4D, mitomycin C was used with PRK. The surgery was performed with an excimer laser (VISX STAR, Abbott Medical Optics, Abbott Park, US). Results: The safety and the efficacy index of the surgery was 1.01 ± 0.05 and 1.00 ± 0.05 in these patients, respectively. All the patients were within ±0.5D of emmetropia 1 year after the surgery. Mesopic contrast sensitivity (CS) had a significant increase in two spatial frequencies of six (P = 0.003) and 12 (P = 0.003). Total coma (P < 0.001), spherical aberration (P < 0.001), and total higher-order aberrations (HOA) (P < 0.001) also showed a significant increase. Corneal hysteresis (P < 0.001) and corneal resistance factor (P < 0.001) showed a significant decrease after 1 year. Conclusion: PRK is a safe, effective, and predictable procedure with desirable effects on mesopic CS in patients with corneal thickness <500 μm, which increases HOAs and decreases corneal integrity proportionate to its value before the procedure.