[Long-term evaluation of laser in situ keratomileusis for extremely high myopia]

To evaluate the long-term efficacy and safety of laser in situ keratomileusis (LASIK) for extremely high myopia (with a preoperative refraction more than -10.00 diopters).

173 eyes of 99 patients with a mean spherical equivalent (SE) of (-13.70 +/- 3.60) D (range -10.00 approximately 23.50 D), including 41 eyes with more than -15.00 D, were treated with LASIK and followed up for more than 18 months. The examinations included slitlamp microscopy, fundus examination, Orbscan II corneal topography system, tonometry, pachymetry, cycloplegic and subjective refraction.

At 18 months postoperatively, the uncorrected visual acuity (UCVA) was 0.5 or better in 148 eyes (85.6%), and the best spectacle-corrected visual acuity (BSCVA) remained the same or increased in 147 eyes (84.4%). No eye lost more than two lines of BSCVA. 109 eyes (63.0%) were within +/- 1.00 D of emmetropia. The percentage was 73.5% and 29.3% in eyes with a preoperative SE of less than -14.75 D and more than -15.00 D, respectively. Postoperatively, the posterior corneal surface bulge was detected in all eyes. The mean elevation of the posterior corneal surface against the best-fit sphere was (0.029 +/- 0.010) mm preoperatively, (0.069 +/- 0.031) mm at 3 months, (0.065 +/- 0.025) mm at 18 months. At final follow-up, corneal flap folds were found in 2 eyes, and 6 patients (10 eyes) complained of glare or decreased scotopic vision.

LASIK appeared to be an effective and safe treatment for correction of extremely high myopia. Meanwhile the candidates should be carefully screened.