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Journal of Ophthalmology
Volume 2016 (2016), Article ID 2672980, 7 pages
Clinical Study

Comparison of the Early Clinical Outcomes between Combined Small-Incision Lenticule Extraction and Collagen Cross-Linking versus SMILE for Myopia

1Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
2Department of Ophthalmology, Hong Kong Eye Hospital, Kowloon, Hong Kong
3Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong
4Hong Kong Laser Eye Center, Kowloon, Hong Kong

Received 21 February 2016; Revised 30 March 2016; Accepted 7 April 2016

Academic Editor: Vasilios F. Diakonis

Copyright © 2016 Alex L. K. Ng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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 (). At 6 months, no eyes lost more than 1 line in corrected distance visual acuity. The safety index was and in SMILE Xtra and control, respectively (). 89% and 94% of eyes were within ±0.50 D of target refraction, respectively, with the mean error in SEQ correction being  D for SMILE Xtra and  D for control (). The efficacy index was and , respectively (). 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.