Tomography Can Help Evaluate Long-Term Outcomes of SMILE Surgery

New Vision clinic, main center for refractive surgery in France, with cutting-edge technology for all eye laser operations. Eye operation using the SMILE, Small Incision Lenticule Extraction, laser technique. It is a new generation of treatment which enables short-sightedness to be corrected without removing the superficial layer of the cornea, nor opening it. The SMILE technique involves producing with the Femtosecond laser, a lenticule, thin slice, in 3D in the thickness of the cornea, and removing it with a micro incision in the shape of a smile. The worse the short-sightedness, the thicker the lenticule. (Photo by: BSIP/Universal Images Group via Getty Images)
The technology was reliable for these patients, except for trefoil, the study shows.

Tomography can accurately visualize and quantify higher-order aberrations (HOAs) across the cornea associated with small incision lenticule extraction (SMILE) surgery, findings published in Eye and Vision suggest.

Previous research concluded that total HOAs, coma, and spherical aberration increase significantly for patients after undergoing SMILE procedures. After surgery, improvements in vision can be accompanied by visual effects, such as halos, glare, reduced contrast sensitivity, and poor night vision, according to the researchers. As such, analyzing corneal aberrations can help inform and predict long-term visual outcomes of SMILE surgery.

The tomography examinations employed a technology that is based on Scheimpflug imaging combined with Placido-based reflection. Investigators have previously reported that the system delivers “good to excellent” intrasession repeatability and reproducibility of anterior segment measurements in healthy, post-refractive surgery (PRK/LASIK) and keratoconus patients.

To examine the precision of corneal morphology measurements in more detail, researchers enrolled 75 eyes of patients who had undergone SMILE surgery. The research team captured 3 consecutive corneal aberrometric measurements with the Scheimpflug-Placido topographer. They report that the repeatability of measurements of anterior and total corneal aberrations in the corneas after SMILE surgery was high, except for trefoil. However, they observed variability in posterior corneal aberrometric measurements. 

The limitations of this study include the possibility of decreased precision, such as misalignment or movement during scanning, short acquisition time, pupil translation, and tear film instability. In addition, the study only included younger patients (18 to 41 years) who experienced a complication-free recovery after SMILE.


Ning R, Gao R, Piñero DP, et al. Repeatability and reproducibility of corneal higher-order aberrations measurements after small incision lenticule extraction using the Scheimpflug-Placido topographer. Eye and Vis. Published online January 4, 2022. doi:10.1186/s40662-021-00274-y.