title: Comparison of photorefractive keratectomy for myopia using 5 mm and 6 mm diameter ablation zones.
abstract: BACKGROUND
  We compared the 5 mm and 6 mm ablation zones of the Summit Omnimed in the treatment of myopia in 2 eyes of the same patient.
  
  
  METHODS
  One hundred and twenty-four consecutive patients with myopia less than 6 diopters (D) has one eye treated with a 5 mm ablation zone and the other eye with a 6 mm ablation zone. Minimum follow up was 6 months.
  
  
  RESULTS
  Follow-up was achieved in 101 patients of the total 124. In the 5 mm group 79% achieved 20/30 uncorrected visual acuity while 68% of the 6 mm group achieved 20/30 acuity. Ninety-seven percent of all eyes in both groups achieved 20/40. Some of the disparity between the 20/30 acuity in the two groups is that initial corrections with the 6 mm zones were conservative. Corneal haze was less in the 6 mm group; subjectively they had better night vision.
  
  
  CONCLUSIONS
  Both lasers with the different ablation zones gave reasonably predictable correction of myopia of up to -6 D. Overcorrection and corneal haze were less in the 6 mm group and night vision was subjectively better.
authors.forename: A T
authors.initials: AT
authors.lastname: Morris
authors.forename: C P
authors.initials: CP
authors.lastname: Ring
authors.forename: O B
authors.initials: OB
authors.lastname: Hadden
mesh_terms: D003318:Corneal Opacity / Q000209:etiology; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000295:instrumentation / Q000379:methods*; D011183:Postoperative Complications / Q000209:etiology; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology