Excimer laser surface ablation safe for thin corneas, long-term study finds

Am J Ophthalmol. 2009;147(5):768-773.

Excimer laser surface ablation has shown long-term safety and efficacy in correcting myopia on corneas thinner than 500 µm, a study found.

The retrospective study looked at 10 years of follow-up on 75 eyes of 49 patients who had a preoperative central corneal thickness of 481.54 ± 15.7 µm (range, 438 µm to 499 µm).

Patients previously had surface ablation for correction of myopia. Measured outcomes were stability of visual acuity and refraction, predictability, corneal keratometry, efficacy, safety and postoperative complications at 3 months and 1, 2, 5 and 10 years postop.

"The safety index improved over the 10-year period and was always higher than 0.9," the study authors said. "The efficacy index remained stable around 0.8. The topography did not show signs of corneal ectasia, and the keratometry showed no increase in corneal power."

Best corrected visual acuity significantly improved postop (P < .01); compared with 3-month results, UCVA had significant improvements at all visits.

In sphere and cylinder results, comparison of 3 months and 10 years postop data had a "slight but significant regression (P < .01)," the study authors said.

At 10 years postop, they found 30 eyes (40%) within 0.5 D of emmetropia and 43 eyes (57.33%) within 1 D.

In addition, 30 eyes (40%) required an enhancement.