Hyperopia correction by noncontact holmium: YAG laser thermal keratoplasty: five-pulse treatments with 1-year follow-up

Graefes Arch Clin Exp Ophthalmol. 1997 Nov;235(11):702-8. doi: 10.1007/BF01880669.

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.

Conclusion: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cornea / physiopathology
  • Cornea / surgery*
  • Corneal Topography
  • Female
  • Follow-Up Studies
  • Humans
  • Hyperopia / physiopathology
  • Hyperopia / surgery*
  • Laser Coagulation* / methods
  • Male
  • Middle Aged
  • Postoperative Complications
  • Reproducibility of Results
  • Safety
  • Treatment Outcome
  • Visual Acuity / physiology