Comparison of Visual, Refractive and Ocular Surface Outcomes Between Small Incision Lenticule Extraction and Laser-Assisted In Situ Keratomileusis for Myopia and Myopic Astigmatism

Abstract

Laser-assisted in situ keratomileusis (LASIK) is the most commonly performed laser refractive surgical technique worldwide for the treatment of myopia and myopic astigmatism. In recent years, small incision lenticule extraction (SMILE) has emerged as a promising alternative to LASIK, requiring only a single femtosecond laser to create an intrastromal lenticule, which is then removed via a small incision. The technique obviates the need for a corneal flap. A number of published studies have compared the two techniques in terms of visual, refractive and ocular surface outcomes. This review compares the clinical outcomes between LASIK and SMILE in treating myopia and myopic astigmatism based on studies published in the last 5 years. Twenty-two studies were included, all of which were observational in nature. Results suggest that the two techniques have comparable visual outcomes in terms of safety, efficacy and predictability, although recovery in visual acuity may be slower in SMILE-treated than LASIK-treated eyes. SMILE is found to result in less severe postoperative dry eye symptoms and faster recovery of corneal sensitivity than LASIK. It is important to note, however, that the SMILE technique is limited by the lack of a cyclotorsion-compensation system and option for customized treatment profile. The heterogeneity of results in this review may be attributable to the use of different LASIK platforms in different studies. Few studies compared the outcomes regarding severity of myopia. Future prospective randomized controlled trials with a larger sample size and longer follow-up period will be highly beneficial for progress in this field.

Recent developments in regenerative ophthalmology

“…Lau et al recently reviewed 22 recent studies comparing the clinical outcomes in LASIK and SMILE for myopia and myopic astigmatism. They found that the two techniques are comparable; SMILEtreated eyes experienced lower severe postoperative dry eye symptoms and faster recovery of corneal sensitivity while LASIK-treated eyes experienced faster recovery of visual acuity (Lau et al, 2019).…”

“…Damgaard et al suggested that prior corneal crosslinking (CXL) induction of SMILE-derived lenticules may reduce time to refractive stabilization, but it also requires longer postoperative steroid treatment (Damgaard et al, 2019). However, additional research is needed to confirm if the additional CXL step reduces the incidence of iatrogenic keratectasia (Lau et al, 2019).…”

Consistency evaluation of intraocular lens power calculation methods in eyes that have undergone small-incision lenticule extraction

“…So, the accurate calculation of IOL power for these patients would be very important soon. Small incision lenticule extraction (SMILE) surgery was firstly reported by Sekundo [2] and Shah [3] in 2011, it is popular for excellent visual outcomes, superior biomechanics, faster recovery of dry eye and corneal nerve reinnervation [4]. Over 2 million patients have undergone SMILE, including 1 million Chinese patients.…”

The Differential Expression of Cytokines and Growth Factors After SMILE Compared With FS-LASIK in Rabbits

“…Femtosecond LASIK (FS-LASIK) is the most popular laser refractive surgery with established safety and efficacy. 1 Recently, small incision lenticule extraction (SMILE) was approved by the US Food and Drug Administration for myopic correction up to –10.0 diopters and myopic astigmatism up to –3.0 diopters. Compared with FS-LASIK, SMILE protects from traumatic flap displacement risk using a 2-mm stromal incision.…”

“…However, studies have reported slower recovery of visual acuity after SMILE than that after FS-LASIK, even with laser-scanning pattern optimization. 1 , 2 , 9 Ang et al 10 reported that postoperative symptoms, such as fluctuation and occasional blurring of vision, were more significant at 1-month postoperation for SMILE than for FS-LASIK. As an elective surgical procedure to restore uncorrected visual acuity and improve quality of life, delayed recovery after SMILE may affect patient satisfaction.…”