Influence of preoperative keratometry on refractive results after laser-assisted subepithelial keratectomy to correct myopia

Purpose: To study the relationship between preoperative keratometry and residual spherical equivalent (SE) after myopic laser-assisted subepithelial keratectomy (LASEK). Setting: Vissum Madrid, Madrid, Spain. Methods: This retrospective study comprised 1149 consecutive eyes that had LASEK to correct myopia. The relationship between preoperative keratometry and the 3-month postoperative SE was analyzed by linear regression. The same analysis was performed in the first decile (percentile 10) with the flattest keratometry readings, in the decile with the steepest readings, and in the quartiles with the lowest and highest preoperative myopia. Results: Preoperatively, the mean SE was -4.59 diopters (D) ± 2.80 (SD) (range -0.25 to -13.00 D) and the mean keratometry, 44.20 ± 1.60 D (range 39.00 to 49.00 D). Three months postoperatively, the mean SE was +0.05 ± 0.50 D. There was a significant (P = .04), although weak (r² = 0.003), correlation between the mean preoperative keratometry and residual SE. Linear regression showed a positive significant correlation within each decile. The correlation was weak in the decile with the flattest corneas (115 eyes) (r² = 0.04, P = .04) and slightly stronger in the decile with the steepest corneas (115 eyes) (r² = 0.1, P = .001) (ie, the steeper the cornea, the greater the overcorrection). There was a weak correlation in the group with higher preoperative myopia (r² = 0.05, P = .0003) but no correlation in the lower myopia group (P = .3). Conclusion: Preoperative corneal curvature did not seem to influence the spherical refractive outcomes after myopic LASEK.