Femtosecond LASIK increases higher-order aberrations more than SMILE

Small-incision lenticule extraction and femtosecond laser-assisted LASIK for myopia yielded different changes in anterior corneal shape, but SMILE increased higher-order aberrations to a lesser extent than LASIK, according to a study.

The retrospective study included 736 eyes of 368 patients treated with SMILE and 148 eyes of 74 patients treated with femtosecond LASIK.

A VisuMax femtosecond laser (Carl Zeiss Meditec) was used in all SMILE procedures and for LASIK flap creation. The MEL 80 excimer laser (Zeiss) was used to perform ablation in the LASIK procedures.

Corneal curvature, corneal power calculations and higher-order aberrations were measured preoperatively and 3 months postoperatively.

There were significant corneal curvature changes in the anterior corneal surface in both groups, but not in the posterior corneal surface. The sagittal curvature was constant for the central 4-mm diameter after SMILE, whereas the curvature showed gradual steepening with increasing diameter in the LASIK group.

Corneal power calculations differed between the groups, depending on the measurement diameter.

All aberrations on the anterior corneal surface increased significantly with both procedures. However, the increases were significantly greater in the femtosecond LASIK eyes.

Measured in a 5-mm zone, femtosecond LASIK yielded 0.11 µm more coma (P < .001) and 0.13 µm higher spherical aberration (P < .001) than SMILE. Other higher-order aberrations on the anterior corneal surface were similar between the groups.

Changes in higher-order aberrations in the posterior cornea were negligible. – by Matt Hasson

Disclosure: The authors report no relevant financial disclosures.

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Source:

Gyldenkerne A, et al. J Refract Surg. 2015;doi:10.3928/1081597X-20150303-01.