Whilst Femto-LASIK and Trans PRK / No Touch LASEK use an excimer laser to reshape the cornea, SmILE uses a femtosecond laser to cut a 3D lenticule inside the cornea. This lenticule is then extracted through a keyhole corneal superficial incision created on the periphery of the cornea. The lenticule cut by the Zeiss Visumax laser is similar to the volume of tissue in excimer laser surgery (Femto-LASIK/ Trans PRK no touch LASEK). The lenticule removed creates a shape change within the cornea and results in focusing of the vision. Within few hours the surface layer (epithelium) begins to grow over the 3mm incision and seals the tunnel.
SmILE in the above diagram step 1-2: In a single step, the VisuMax Zeiss Femto laser creates a refractive lenticule and a small incision of less than 3 mm within the thickness of the intact cornea.
SmILE step 3: The lenticule is removed through the small incision. The disruption to the biomechanics of the cornea is minimal. No flap is cut like in Femto-LASIK.
SmILE combines some of the advantages of Femto-LASIK (relative rapid recovery) and Trans-PRK (safe early return to contact sports). SmILE cannot yet be used to correct long-sight. SmILE is proposed to have possible advantages over Femto-LASIK and Trans-PRK for patients with myopia and astigmatism in the higher range (above -1.50). Please note that refinement treatment (treating any residual need for glasses after surgery) after SmILE is usually performed with Trans PRK or in some cases with Femto-LASIK.