Vol 37 No. 2 Original Article PDF

Comparing Femtosecond Lenticule Extraction (FLEx) and Femtosecond Laser In-situ Keratomileusis (LASIK) for Myopia and Astigmatism

Tina Marie Saban-Roa, MD, Irwin Cua, MD, and Ruben Lim Bon Siong, MD

Objective

To compare the efficacy, safety, predictability, stability, contrast sensitivity, and higher-order aberration (HOA) of patients who had femtosecond lenticule extraction (FLEx) and femtosecond laser in-situ keratomeleusis (LASIK) for the correction of moderate myopia and astigmatism.

Methods

A retrospective review of charts was conducted at the Vision Laser Center of the St. Luke’s Medical Center-Global City. All patients that underwent FLEx from November 2011 to June 2012, with adequate follow-up, were included in the study. Age-matched and refraction-matched patients, who underwent femtosecond LASIK in the same review period, were chosen as comparators. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), attempted refraction versus achieved refraction, contrast sensitivity, HOA, and adverse events were compared preoperatively and one-day, one-week, one-month, and three-month postoperatively in both groups.

Results

Twenty-six eyes of 13 patients who underwent FLEx and 22 eyes of 11 patients who underwent femto-LASIK were included in the study. The preoperative mean spherical equivalent were -4.61 ± 1.17 D (range -2.50 D to -6.75 D) and -5.30 ± 1.14 D (range -2.63 to -6.88) for the FLEx and the femto-LASIK groups respectively. At 1-day postoperatively, 12% and 100% achieved UCVA of 20/30 or better in the FLEx and femto-LASIK groups respectively. At 3 months follow-up, 96% achieved UCVA of 20/32 or better in the FLEx group and 3% lost >2 lines and 23% lost 1 line of BCVA. None in the femto-LASIK group lost any line of BCVA. Mean spherical equivalent after 3 months was +0.06 ±0.21 D in the FLEx and -0.44 ±0.35 D in the femto-LASIK groups (p<0.001). HOA, analyzed as root mean square (RMS), were similar preoperatively and postoperatively in both groups. Contrast sensitivity increased postoperatively in the lower spatial frequencies for both groups but were similar in the higher spatial frequencies. No adverse events were noted in either group.

Conclusions

FLEx was comparable to femtosecond LASIK in terms of visual outcomes in the treatment of moderate myopia and astigmatism. The FLEx group showed better accuracy and stability within the three-month follow-up period. However, delayed visual improvement and loss of BCVA were noted.

Keywords:Femtosecond lenticule extraction, femtosecond LASIK, myopia, astigmatism