EXCIMER-LASER TREATMENT FOR HIGH AND EXTREME MYOPIA

Objective: The excimer laser allows the controlled ablation of corneal tissue to correct refractive error. We assessed the efficacy of excimer laser treatment for persons with high (spherical equivalent between -5 and -10 diopters) and extreme (spherical equivalent greater than -10 D) myopia. Methods: Patients were assessed 1, 3, and 6 months postoperatively. A VisX Twenty/Twenty laser was used. Visual acuity, refraction, corneal clarity, and adverse reactions were evaluated at each visit. Results: Six month follow-up data were available for 194 high myopes and 53 extreme myopes. Postoperative healing was similar for the two groups. Six months postoperatively, 89.2% of high myopes and 49% of extreme myopes were within 2 D of planned refraction. At 6 months, 28% of high myopes had an uncorrected visual acuity of 20/20 and 71% had an uncorrected visual actuity of 20/40. Of extreme myopes, 4% had an uncorrected visual acuity of 20/20 and 30% had an uncorrected visual acuity of 20/40. Significantly more corneal haze was observed in the extreme myopes. Loss of 2 or more lines of best corrected visual acuity was observed in 13% of high myopes and 13% of extreme myopes at 6 months. Conclusions: Excimer laser photorefractive keratectomy is an alternative means bf treating high and extreme myopia and can cause a significant reduction in myopia. There is a need to gather further information as more patients are followed up for greater time.