title: Hyperopia correction by noncontact holmium: YAG laser thermal keratoplasty: five-pulse treatments with 1-year follow-up.
abstract: BACKGROUND
  Previous noncontact holmium (Ho): YAG laser thermal keratoplasty (LTK) studies on correction of low to moderate hyperopia have used treatment algorithms based on ten-pulse, variable-pulse-energy treatment parameters. The purpose of this study was to evaluate the safety, effectiveness, and stability of new five-pulse, constant-pulse-energy treatment parameters for noncontact Ho:YAG LTK.
  
  
  METHODS
  Thirty-nine hyperopic patient eyes [up to +4.75 diopters (D) refractive error] were treated using simultaneous noncontact delivery of Ho:YAG laser energy (Sunrise) with two symmetrical octagonal rings of eight spots per ring and radial spot patterns on centerline diameters of 5 and 6 mm (group A), 6 and 7 mm (group B), or 6.5 and 7.5 mm (group C). Each ring of spots received five pulses of laser light at 5 Hz pulse repetition frequency and a fixed pulse energy of 240 mJ. Thirty of the 39 patient eyes (77%) had 1-year follow-up exams.
  
  
  RESULTS
  At 1 year, the mean Snellen uncorrected distance visual acuity lines gained was 3.7 +/- 0.5/6.8 +/- 2.7/5.3 +/- 3.3 for groups A, B, and C. The mean changes in subjective manifest refraction (spherical equivalent) were -2.08 +/- 1.13 D, -1.83 +/- 0.88 D, -1.22 +/- 0.88 D for groups A, B, and C respectively. None of the eyes lost two or more lines of spectacle-corrected distance visual acuity. There were no clinically significant complications in any patient.
  
  
  CONCLUSIONS
  This clinical study indicates that five-pulse noncontact LTK treatments of low hyperopia are safe and effective. The stability has to be confirmed with longer follow-up.
authors.affiliation: Cullen Eye Institute, Baylor College of Medicine, Department of Ophthalmology, Houston, Texas, USA. TBKMD@aol.com
authors.forename: T
authors.initials: T
authors.lastname: Kohnen
authors.forename: R
authors.initials: R
authors.lastname: Villarreal
authors.forename: R
authors.initials: R
authors.lastname: Menefee
authors.forename: M
authors.initials: M
authors.lastname: Berry
authors.forename: D D
authors.initials: DD
authors.lastname: Koch
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology / Q000601:surgery*; D017075:Laser Coagulation / Q000379:methods; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D015203:Reproducibility of Results; D012449:Safety; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology