Noncontact holmium: YAG laser thermal keratoplasty to correct hyperopia: 18-month follow-up

Thomas Kohnen, Douglas D. Koch, Peter J. McDonnell, Richard F. Menefee, Michael J. Berry

Research output: Contribution to journalArticlepeer-review


To assess the safety and efficacy of noncontact holmium:yttrium aluminium garnet laser thermal keratoplasty (Ho: YAG LTK) for correction of low to moderate hyperopia. Methods: We performed noncontact Ho:YAG LTK on 1 eye each of 28 patients for correction of hyperopia up to +3.88 dpt. Treatments were conducted with 1 or 2 symmetrical octagonal rings of 8 spots/ring with centerline diameters of 6 mm (1 ring) or 6 and 7 mm (2 rings), 10 pulses of laser light at 5 Hz pulse repetition frequency, variable pulse energy in the range of 208-242 mJ and a nominal spot diameter between 615 and 623 ±m. Results: At 18 months after surgery, 20 of 22 (91%) treated patient eyes had improved uncorrected distance visual acuity The mean change in subjective manifest refraction (spherical equivalent) was −0.52 ± 0.35 dpt and −1.41 ± 0.53 dpt for 1- and 2-ring treatment groups, respectively, with good stability in the refractive change after 6 months. The mean induced refractive astigmatism was small (0.30 ± 0.37 dpt/0.25 ± 0.29 dpt for 1-/2-ring treatments). None of the eyes lost 2 or more lines of spectacle-corrected distance visual acuity. There were no clinically significant changes in glare and contrast sensitivity. Conclusions: Noncontact LTK treatment of low hyperopia is safe and effective, and it is more stable and less prone to induce astigmatism than previously reported contact mode LTK treatments.

Original languageEnglish (US)
Pages (from-to)274-282
Number of pages9
Issue number5
StatePublished - Jan 1 1997
Externally publishedYes


  • Holmium:YAG laser
  • Hyperopia
  • Laser thermal keratoplasty
  • Thermal keratoplasty
  • Thermokeratoplasty

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems


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