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.
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Authors | T Kohnen, R Villarreal 5th, R Menefee, M Berry, D D Koch |
Journal | Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie
(Graefes Arch Clin Exp Ophthalmol)
Vol. 235
Issue 11
Pg. 702-8
(Nov 1997)
ISSN: 0721-832X [Print] Germany |
PMID | 9407228
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Topics |
- Adult
- Aged
- Cornea
(physiopathology, surgery)
- Corneal Topography
- Female
- Follow-Up Studies
- Humans
- Hyperopia
(physiopathology, surgery)
- Laser Coagulation
(methods)
- Male
- Middle Aged
- Postoperative Complications
- Reproducibility of Results
- Safety
- Treatment Outcome
- Visual Acuity
(physiology)
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