title: Comparison of the Early Clinical Outcomes between Combined Small-Incision Lenticule Extraction and Collagen Cross-Linking versus SMILE for Myopia.
abstract: Background. To compare the early outcome of combined SMILE and collagen crosslinking (SMILE Xtra) with SMILE. Method. Prospective, comparative interventional study of 21 eyes receiving SMILE Xtra using a low energy protocol and 32 control eyes receiving SMILE only. The outcomes were compared at 1, 3, and 6 months postoperatively. Results. Both groups had myopia with spherical equivalent refraction (SEQ) > 4.00 D. The SMILE Xtra group had thinner preoperative central corneal thickness and residual stromal bed thickness (p < 0.021). At 6 months, no eyes lost more than 1 line in corrected distance visual acuity. The safety index was 0.96 ± 0.06 and 1.00 ± 0.00 in SMILE Xtra and control, respectively (p < 0.001). 89% and 94% of eyes were within ±0.50 D of target refraction, respectively, with the mean error in SEQ correction being -0.17 ± 0.26 D for SMILE Xtra and +0.03 ± 0.25 D for control (p = 0.021). The efficacy index was 0.88 ± 0.13 and 0.97 ± 0.06, respectively (p = 0.005). Conclusion. SMILE Xtra had good overall safety profile and predictability at 6 months. However, when compared with control, the safety index and efficacy index were statistically significantly lower in the early postoperative period.
authors.affiliation: Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Alex L K
authors.initials: AL
authors.lastname: Ng
authors.affiliation: Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong; Department of Ophthalmology, Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Tommy C Y
authors.initials: TC
authors.lastname: Chan
authors.affiliation: Hong Kong Laser Eye Center, Kowloon, Hong Kong.
authors.forename: George P M
authors.initials: GP
authors.lastname: Cheng
authors.affiliation: Department of Ophthalmology, Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Vishal
authors.initials: V
authors.lastname: Jhanji
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.
authors.forename: Cong
authors.initials: C
authors.lastname: Ye
authors.affiliation: Hong Kong Laser Eye Center, Kowloon, Hong Kong.
authors.forename: Victor C P
authors.initials: VC
authors.lastname: Woo
authors.affiliation: Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Jimmy S M
authors.initials: JS
authors.lastname: Lai