Thoughts on small-incision lenticule extraction (SMILE)
Dr Alio: Treatment of hyperopia remains challenging for refractive surgeons. Hyperopic small-incision lenticule extraction (SMILE) performed using a proprietary femtosecond laser has recently been proposed and developed as a new treatment option. Clinical data from the first clinical trials are now being reported, bringing the technique closer to the clinic.
However, although encouraging results have been seen and will likely lead to a change in hyperopia management in the near future, there are still some important concerns, such as central haze, that need to be addressed. Further light might be shed on this in the coming year, as long-term outcomes and regression rate data become available.
Dr Alio: There are still some concerns regarding the available surgical options for SMILE enhancements. Important evidence has recently been published regarding the efficacy and safety of photorefractive keratectomy (PRK) after SMILE.
Visual recovery takes a little longer with SMILE (sometimes longer than acceptable) than with LASIK, and to convert into LASIK by opening the interface is not always feasible. We should be aware of future SMILE improvements such as cyclotorsion control to improve astigmatic outcomes; reSMILE standardisation to improve enhancement outcomes; and software optimisations to reduce the tissue comsumption per diopter.
Dr Fazio: SMILE is a relatively new treatment that has been proposed as a means to overcome the troubles encountered with the old and trusty LASIK and PRK. But will it be able to honour this promise?
SMILE has its limitations, including a slower recovery time compared with LASIK; difficult hyperopia treatment; and complications such as retained lenticule fragments. Moreover, it is not an open technique; it is a machine-linked procedure requiring the surgeon to use a femtosecond laser system (for example, Zeiss’ Visumax) if he or she wants to embrace the philosophy within.
Since there is not yet a validated way to analyse the biomechanical impact of a SMILE procedure compared with a PRK- or LASIK-guided procedure, the jury is still out. It is true that corneal analysis by the Corvis ST (Oculus) reveals a lesser impact of SMILE on the stiffness of the cornea but it is not yet clear if Corvis ST’s results can powerfully predict eventual ectasia.