SMILE With Low Energy Levels: Assessment of Early Visual and Optical Quality Recovery

Abstract

To assess early visual and optical quality recovery according to preoperative refraction after small incision lenticule extraction (SMILE) at low energy level for myopia and myopic astigmatism treatment. This prospective study included 101 eyes of 101 patients separated into three groups: low myopia (30 eyes), with a mean spherical equivalent (SE) of -2.13 ± 0.73 diopters (D); moderate myopia (33 eyes), with a mean SE of -4.53 ± 0.86 D; and high myopia (38 eyes), with a mean SE of -6.54 ± 0.78 D. Visual acuity, contrast sensitivity, refraction, corneal higher order aberrations, modulation transfer function, Strehl ratio, and Objective Scatter Index (OSI) were measured. All eyes had a corrected distance visual acuity of 20/20 or better at 1 day in the low myopia group and 1 month in the moderate and high myopia groups. The contrast sensitivity preoperative values recovered at 8 days in the low myopia group and 1 month in the moderate and high myopia groups. At 1 month, the low myopia group recovered the OSI preoperative values (0.61 to 0.69) and the OSI values were slightly higher than the preoperative value in the moderate and high myopia groups (0.74 to 1.00 and 0.8 to 1.14, respectively). The recovery time of visual and optical quality in the first month after SMILE correlated with preoperative refraction and the amount of postoperative scattering. Patients with low myopia recovered visual acuity faster and with less ocular scattering than patients with moderate or high myopia. [J Refract Surg. 2019;35(5):285-293.].