Overview of Clinical Results for Low and Moderate Myopia

Abstract

During the last few years, small-incision lenticule extraction (SMILE) has become clinically available in Europe and Asia as an alternative to LASIK for correction of myopia. In the United States, the procedure is currently undergoing clinical trials for approval by the US Food and Drug Administration. In SMILE, a femtosecond laser is used to create an intrastromal lenticule that is manually extracted through a small peripheral incision (see Chap. 5) [1, 2]. Being flap-free, this surgical approach may reduce some of the side effects of LASIK, such as dry eye (Fig. 7.1), flap dislocation [3], reduced sensitivity and subbasal nerve fiber density (see Chap. 3) [4], and corneal ectasia [5]. The efficacy, predictability, and safety of the procedure have been reported to be on par with femtosecond LASIK [1, 2, 6–9]. However, some studies report a relatively high percentage of eyes with loss of two or more lines in visual acuity [6], and only a few studies have reported complications related to SMILE surgery [10, 11]. Furthermore, SMILE has some advantages over LASIK in dry eye parameters and subjective symptoms, postoperatively (Fig. 7.2) [12, 13]. This review evaluates the early clinical outcomes after SMILE technique in patients with low to moderate myopia; however the vast majority of published results are focused on moderate myopia [1, 2, 14–21]. Only one study on low myopia by Reinstein et al. was found in peer-reviewed literature [21]. It will be discussed separately. In addition, presented but not yet published 5-year results will be shared with the reader.