title: Photorefractive keratectomy for low-to-moderate myopia and astigmatism with a small-beam, tracker-directed excimer laser.
abstract: OBJECTIVE
  To assess the safety and effectiveness of the Autonomous Technologies Corporation LADARVision excimer laser system for photorefractive keratectomy correction of myopia and astigmatism.
  
  
  METHODS
  A multicenter, prospective, noncomparative case series.
  
  
  METHODS
  The cohort consisted of 467 eyes corrected for spherical myopia and 211 eyes corrected for myopia with astigmatism.
  
  
  METHODS
  Treatments were performed at six sites in the United States using a 6-mm ablation zone for spherical myopes and a 5.5-mm zone with a 1.0-mm blend for astigmats.
  
  
  METHODS
  Visual acuity, subjective refraction, corneal haze, intraocular pressure, complications, adverse reactions, patient satisfaction, and corneal endothelial changes.
  
  
  RESULTS
  Twelve-month follow-up was available on 414 spherical eyes and 175 astigmatic eyes. The results for spherical eyes with correction between -1 and -5.99 diopters (D) were: uncorrected visual acuity (UCVA) of 20/40 or better achieved by 98.1%, 20/20 or better by 72%, 1.8% lost 2 lines and 0.3% lost greater than 2 lines of best spectacle-corrected visual acuity (BSCVA); 76.4% were within 0.50 D of the target correction and 94.4% were within 1.00 D. The results for myopia with astigmatism with spherical equivalent correction between -1 and -5.99 D were: UCVA of 20/40 or better in 97.4%, 20/20 or better in 61.7%, 2.5% lost 2 lines and no eyes lost greater than 2 lines BSCVA; 73.9% were within 0.50 D of the target correction and 95% were within 1.00 D. For spherical myopes combined with myopic astigmats corrected for 6 to 10 D, results were: UCVA of 20/40 or better in 93.4%, 20/20 or better in 61.2%, 2.3% lost 2 lines and no eyes lost greater than 2 lines of BSCVA; 67.2% were within 0.50 D of the desired correction and 87.8% were within 1.00 D. Refractive stability was achieved between 3 and 6 months for the spherical and astigmatic groups. No eyes had corneal haze graded as moderate or greater, and there was no significant decrease in endothelial cell density.
  
  
  CONCLUSIONS
  Patients treated for 1 to 10 D of spherical equivalent myopia, with or without astigmatism, showed early refractive stability, excellent UCVA, no significant loss of BSCVA, no loss of endothelial cell density, and very low levels of corneal haze to 12 months after surgery.
authors.affiliation: Refractive Surgery Center of the South, Eye, Ear, Nose and Throat Hospital, New Orleans, Louisiana, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: McDonald
authors.forename: M R
authors.initials: MR
authors.lastname: Deitz
authors.forename: J M
authors.initials: JM
authors.lastname: Frantz
authors.forename: M C
authors.initials: MC
authors.lastname: Kraff
authors.forename: R R
authors.initials: RR
authors.lastname: Krueger
authors.forename: J J
authors.initials: JJ
authors.lastname: Salz
authors.forename: C R
authors.initials: CR
authors.lastname: Kraff
authors.forename: E
authors.initials: E
authors.lastname: Maguen
authors.forename: C S
authors.initials: CS
authors.lastname: Matta
authors.forename: A B
authors.initials: AB
authors.lastname: Nesburn
authors.forename: L W
authors.initials: LW
authors.lastname: Piebenga
mesh_terms: D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000601:surgery*; D002452:Cell Count; D003315:Cornea / Q000601:surgery*; D004728:Endothelium, Corneal / Q000166:cytology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D017060:Patient Satisfaction; D018903:Photorefractive Keratectomy / Q000379:methods*; D011183:Postoperative Complications; D011446:Prospective Studies; D012029:Refraction, Ocular; D012449:Safety; D016896:Treatment Outcome; D014792:Visual Acuity