Refractive lenticule extraction (ReLEx) small-incision lenticule extraction (SMILE) is used to treat myopia, with or without astigmatism.
Laser in situ keratomileusis (LASIK) and its variant, femtosecond LASIK (FS-LASIK), despite their success in providing independence from corrective eyeglasses (spectacles) and contact lenses, has continued to be associated with rare complications, including flap-related complications, postoperative dry eye, denervation of corneal nerves, and biomechanical instability leading to corneal ectasia. Engineers, scientists, and surgeons have continued to study alternatives to LASIK because of these uncommon but potentially serious complications.
Refractive lenticule extraction (ReLEx) was the byproduct of existing applications—automated lamellar keratoplasty, automated in situ keratomileusis, and femtosecond lasers. In 2007, an intrastromal femtosecond lenticule extraction (FLEx) was revisited for patients with extreme myopia. In 2011, a small-incision lenticule extraction (SMILE) procedure was introduced as a third-generation laser refractive surgery procedure. The flap creation was eliminated and replaced with creation of a corneal pocket, in which a lenticule is gently removed from a small keyhole incision, usually 2-4 mm in width. Fewer corneal nerves are severed during creation of the pocket and removal of the lenticule, so dry-eye symptoms and loss of corneal sensitivity may occur less frequently after SMILE.
The VisuMax® Femtosecond Laser System is the only laser approved to perform the SMILE procedure.
The image below shows a comparison of the different treatment steps of SMILE, LASIK, and photorefractive keratectomy (PRK).
SMILE treatment steps in comparison to LASIK and PRK. Courtesy of ZEISS (http://www.zeiss.com/corporate/en_us/home.html).