title: Chronic dry eye in photorefractive keratectomy and laser in situ keratomileusis: Manifestations, incidence, and predictive factors.
abstract: OBJECTIVE
  To evaluate dry-eye manifestations after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and determine the incidence and predictive factors of chronic dry eye using a set of dry-eye criteria.
  
  
  METHODS
  Walter Reed Army Medical Center, Washington, DC, USA.
  
  
  METHODS
  Prospective, non-randomized clinical study.
  
  
  METHODS
  Dry-eye evaluation was performed before and after surgery. Main outcome measures included dry-eye manifestations, incidence, and predictive factors of chronic dry eye.
  
  
  RESULTS
  This study comprised 143 active-duty U.S. Army personnel, ages 29.9 ± 5.2 years, with myopia or myopic astigmatism (manifest spherical equivalent -3.83 ± 1.96 diopters) having PRK or LASIK. Schirmer scores, corneal sensitivity, ocular surface staining, surface regularity index, and responses to dry-eye questionnaire significantly changed over time after PRK. After LASIK, significant changes were observed in tear breakup time, corneal sensitivity, ocular surface staining, and responses to questionnaire. Twelve months postoperatively, 5.0% of PRK and 0.8% of LASIK participants developed chronic dry eye. Regression analysis showed that pre-operatively lower Schirmer score will significantly influence development of chronic dry eye after PRK, whereas preoperatively, lower Schirmer score or higher ocular surface staining score will significantly influence the occurrence of chronic dry eye after LASIK.
  
  
  CONCLUSIONS
  Chronic dry eye was uncommon after PRK and LASIK. Ocular surface and tear-film characteristics during pre-operative examination might help to predict chronic dry-eye development in PRK and LASIK.
  
  
  BACKGROUND
  The authors have no financial interest in any product, drug, instrument, or equipment discussed in this manuscript.
authors.affiliation: From The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA (Bower), Warfighter Refractive Eye Surgery Program and Research Center at Fort Belvoir, Fort Belvoir, Virginia, USA (Sia, Ryan), Ophthalmology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA (Mines), Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA (Dartt). Electronic address: kbower5@jhmi.edu.
authors.forename: Kraig S
authors.initials: KS
authors.lastname: Bower
authors.affiliation: From The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA (Bower), Warfighter Refractive Eye Surgery Program and Research Center at Fort Belvoir, Fort Belvoir, Virginia, USA (Sia, Ryan), Ophthalmology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA (Mines), Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA (Dartt).
authors.forename: Rose K
authors.initials: RK
authors.lastname: Sia
authors.affiliation: From The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA (Bower), Warfighter Refractive Eye Surgery Program and Research Center at Fort Belvoir, Fort Belvoir, Virginia, USA (Sia, Ryan), Ophthalmology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA (Mines), Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA (Dartt).
authors.forename: Denise S
authors.initials: DS
authors.lastname: Ryan
authors.affiliation: From The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA (Bower), Warfighter Refractive Eye Surgery Program and Research Center at Fort Belvoir, Fort Belvoir, Virginia, USA (Sia, Ryan), Ophthalmology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA (Mines), Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA (Dartt).
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mines
authors.affiliation: From The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA (Bower), Warfighter Refractive Eye Surgery Program and Research Center at Fort Belvoir, Fort Belvoir, Virginia, USA (Sia, Ryan), Ophthalmology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA (Mines), Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA (Dartt).
authors.forename: Darlene A
authors.initials: DA
authors.lastname: Dartt
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery; D002908:Chronic Disease; D003315:Cornea / Q000502:physiology; D019781:Corneal Topography; D015352:Dry Eye Syndromes / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D015994:Incidence; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008889:Military Personnel; D009216:Myopia / Q000601:surgery; D018903:Photorefractive Keratectomy / Q000379:methods*; D011183:Postoperative Complications; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013666:Tears / Q000502:physiology; D014481:United States; D055815:Young Adult