Assesssement Of Refractive And Keratometric Errors According To The Most And Least Powerful Axes After Smile Refractive Surgery With A Whith-The-Rule Astigmatism.

To assess the refractive and keratometric errors according in both orthogonal axes after SMILE refractive surgery to correct myopia and with-the-rule (WTR) astigmatism without Ocular Residual Astigmatism (ORA)

Bellecour Vision Clinic, LYON

This retrospective study included 42 eyes of 42 patients. All the eyes had a preoperative myopia with a WTR astigmatism and a topographic astigmatism in the same axis.

Visual acuity (VA), refraction and topography were performed preoperatively, at 1 day and 1 month postoperatively. Refractive and keratometric analysis were evaluated with the cross cylinder method. The refractive or keratometric errors were defined as the difference between the attempted and the achieved refractive or keratometric values.

The mean preoperative spherical equivalent (SE) was -3.80 ± 2.02 diopters (D) with a refractive cylinder of   -1.04 ± 0.85 D. At 1 month postoperatively, mean SE was +0.20 ± 0.33 D with a cylinder of -0.15 ± 0.29 D.

Concerning keratometry, cross cylinder analysis showed an undercorrection of 0.36 ± 0.33 D et 0.69 ± 0.47 D on the least powerful and most powerful axes, respectively.

Concerning refraction, cross cylinder analysis showed an undercorrection of -0.56 ± 0.37 D et -0.94 ± 0.53 D on the least powerful and most powerful axes, respectively.

The undercorrection is significantly greater on the most powerful axis than on the least powerful axis on the keratometry and the refraction. (p<0.05)

This study confirms, for the first time on topographies, an undercorrection of the most powerful axis.