title: Laser thermal keratoplasty for the treatment of photorefractive keratectomy overcorrections: a 1-year follow-up.
abstract: OBJECTIVE
  To evaluate the results of holmium:YAG laser thermal keratoplasty (LTK) treatment for overcorrection of myopia after a photorefractive keratectomy (PRK) treatment.
  
  
  METHODS
  Thirty-six eyes (33 patients) were treated with a nontouch holmium:YAG laser (Sunrise Technologies, Model LTK, Freemont, CA) because of hyperopia (mean +/- standard deviation of +2.06 diopter [D] +/- 0.75, ranging from +1.0 to +3.5 D) following a PRK treatment. A control LTK group treated for primary hyperopia, who had preoperative refraction values not statistically different from the PRK + LTK group, was used for comparison.
  
  
  METHODS
  The number of spots applied varied from 8 to 24, and the energy used was 200 to 240 mJ. A maximum of three rings of four to eight spots were placed between 6 and 8 mm from the visual axis.
  
  
  RESULTS
  Twelve months after the LTK retreatment for PRK patients, mean refraction was +1.14 D +/- 1.09. Regression from 1 to 12 months was 0.5 D +/- 1.1. At 12 months, 50% of eyes were within 1 D of emmetropia; 93% of eyes had uncorrected visual acuity (UCVA) of 20/40 or better; and 24% of eyes had UCVA of 20/20 or better. Refraction was not stable for 11 eyes (34%) that regained original sphere values or higher. Best-corrected visual acuity was not affected, and haze was not increased nor decreased by the procedure.
  
  
  CONCLUSIONS
  Twelve months after an LTK retreatment for an initial PRK, two thirds of the retreated eyes did not need further retreatments. However, clinical data showed that LTK should be kept for +1 to +2 D of hyperopia for PRK overcorrection retreatments.
authors.affiliation: Michel Pop Clinic, Montreal, PQ, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Pop
mesh_terms: D000328:Adult; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000209:etiology / Q000601:surgery*; D017075:Laser Coagulation; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D012029:Refraction, Ocular; D012086:Reoperation; D016896:Treatment Outcome; D014792:Visual Acuity