Purpose
Short-term follow-up studies have shown that the predictability, efficacy, and safety of all-femtosecond laser based corneal refractive procedures for correction of myopia are similar to LASIK. The purpose of the present clinical quality control study was to evaluate the longer-term stability of these procedures.
Methods
90 patients operated on both eyes with femtosecond LASIK (LASIK), femtosecond lenticule extraction (FLEX), or small incision lenticule extraction (SMILE) participated in a follow examination more than one year after surgery. All patients had been treated for moderate to high myopia (-11.00 to -4.50 D of spherical equivalent refraction) in both eyes. 3 months after surgery and at the follow-up visit more than one year after surgery, uncorrected visual acuity (UCVA), manifest refraction, and best corrected visual acuity (BCVA) was measured and changes in refractions, UCVA, and BCVA were calculated.
Results
The average preoperative spherical correction was -7.00 D, cylinder was -0.62 D, and spherical equivalent correction (SEQ) was -7.28 D. There were no significant differences in refractions or BCVA between the three groups before surgery. Post-operative refractive results at 3 months after surgery are shown in Table 1. Changes in UCVA, BCVA, and SEQ were small from 3 months to more than one year of surgery (Table 2). ANOVA tests revealed no significant change in SEQ over the longer-term period after the 3 types of surgery, and there was no significant difference between groups. UCVA improved significantly over the longer-term period in eyes treated with FLEX and SMILE, but not after LASIK. Post hoc tests showed that eyes operated with SMILE improved significantly more than eyes treated with LASIK. BCVA improved in all groups from 3 months to more than one year after surgery. Post hoc tests did not reveal any significant difference between the treatments.
Conclusions
Spherical equivalent refraction was stable from 3 months after surgery. Uncorrected and best spectacle corrected visual acuity improved from 3 months to years after surgery. The longer-term stability of the recently introduced all-femtosecond laser based procedures seems similar to femtosecond-LASIK, and uncorrected visual acuity may even improve more over time in eyes operated with SMILE compared with LASIK.
Keywords: 682 refractive surgery: other technologies •
479 cornea: clinical science •
678 refractive surgery