Poster Abstract

Purpose
To evaluate and compare the clinical outcomes, including visual acuity, refractive errors, and aberrations, and corneal biomechanics between 120 μm and 140 μm cap in small incision lenticule extraction (SMILE).
Methods
A hundred fifty eyes of 150 patients (91 eyes with 120 μm, and 59 eyes with 140 μm) were treated with 120 μm cap thickness or 140 μm cap thickness SMILE. Safety, efficacy, predictability, and corneal aberrations were compared between the two groups. Corneal biomechanics changes were evaluated with Corvis ST (Oculus, Wetzlar, Germany).
Results
At 6 months after surgery, the mean logMAR UDVA was comparable, at -0.13 ± 0.06 and -0.13 ± 0.06, in the 120 μm and 140 μm groups, respectively. Safety, efficacy, and predictability of refractive and visual outcomes were also comparable in both groups. Corneal total root mean square (RMS) aberration, and corneal spherical aberration were significantly higher in the 140 μm group, than the 120 μm group. Changes of corneal biomechanics between preoperative and postoperative period, were significant in both groups. Deformation amplitude ratio and integrated inverted radius were more affected in the 140 μm group.
Conclusion
SMILE with both cap thickness is predictable and effective for correction of myopic eyes. Induction of corneal higher order aberrations and changes of corneal biomechanics were higher in thick cap thickness group.