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The correction of high myopia using the excimer laser
J Heitzmann1, P S Binder, B S Kassar
1Mericos Eye Institute, Scripps Memorial Hospital, La Jolla, Calif.
Archives of Ophthalmology (Chicago, Ill. : 1960)
|December 1, 1993
Summary
Excimer laser photorefractive keratectomy for high myopia (>-8.00 D) showed lower efficiency and predictability than for lower myopia. This study found increased regression and corneal haze, suggesting the multizone approach did not prevent these complications.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Corneal Surgery
Background:
- High myopia, defined as a refractive error greater than -8.00 diopters (D), presents unique challenges for surgical correction.
- Excimer laser photorefractive keratectomy (PRK) is a common procedure for myopia correction, but its efficacy in high myopia is less established.
Purpose of the Study:
- To evaluate the safety and efficacy of excimer laser photoablation for correcting high myopia.
- To assess the predictability and potential complications of PRK in patients with severe myopia.
Main Methods:
- A cohort of 23 eyes from 18 patients with high myopia (>-8.00 D) underwent PRK using a multizone protocol with an excimer laser.
- Preoperative spherical equivalent refractions ranged from -8.00 D to -19.50 D, with a mean attempted ablation depth of 93.0 microns.
Main Results:
- Postoperatively, the mean spherical equivalent refraction was -1.09 D.
- Uncorrected visual acuity of 20/40 or better was achieved in 52% of eyes.
- Corneal haze was observed in 47% of eyes, and 39% of eyes were within +/- 1.00 D of the attempted correction.
Conclusions:
- Photorefractive keratectomy for high myopia is less efficient and predictable compared to its use in low myopia.
- A higher incidence of refractive regression and corneal haze was observed in high myopia cases.
- The multizone approach to reduce ablation depth did not prevent subsequent haze or refractive regression in eyes with myopia greater than -8.00 D.