Long-term course of contrast sensitivity in eyes after laser-assisted in-situ keratomileusis for myopia

To evaluate the long-term contrast sensitivity (CS) after laser in-situ keratomileusis (LASIK) for myopia.

This retrospective, single-center, cohort study involved 190 eyes of 95 patients who underwent bilateral LASIK between January 2001 and October 2007. This study includes patients who underwent CS and higher-order aberration (HOA) measurements in a five-year postoperative period. For all enrolled patients, visual acuity, refractive error (RE) in diopters (D), CS at 3-, 6-, 12-, and 18-cycles per degree (cpd), and HOA in a 4 mm area of the dilated pupil were measured before surgery and 6 months, 1 year, and 5 years after it.

The mean RE measured before the surgery and after 6 months, 1 year, and 5 years after was -6.08 ± 2.50D, -0.26 ± 0.65D, -0.28 ± 0.65D, and -0.48 ± 0.80D, respectively. There were no clinically significant changes between preoperative results and the measures taken 6 months, 1 year, and 5 years after surgery. The slight increase in HOA had little effect on CS over the mid to long-term postoperative period.

Our findings show that CS does not clinically change post LASIK. Although we were unable to identify the specific mechanism, we theorize that after LASIK there is a possibility for the compensation of HOA.