title: Photorefractive keratectomy results in myopic patients with thin cornea eyes.
abstract: 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).
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran University of Medical Sciences, International Campus, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran University of Medical Sciences, International Campus, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Miraftab
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, International Campus, Tehran, Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Asgari
keywords: Higher order aberrations; mesopic contrast sensitivity; photorefractive keratectomy; thin cornea