Small-incision lenticule extraction (SMILE) has risen to fame as a safer alternative to LASIK for correcting myopia and astigmatism, but this technique—and corneal refractive surgery in general—sometimes results in increased higher-order aberrations (HOAs), such as coma and spherical aberration, which decrease vision quality. Considering the effectiveness of this procedure in high myopes, a recent study found that SMILE didn’t alter the amplitude of accommodation, accommodative response or accommodative facility in these patients, nor did surgically induced corneal HOAs affect these patients’ accommodative function.
A research team from Denmark and Singapore enrolled 35 highly myopic eyes (a myopic spherical equivalent of at least 6.00D) and 35 healthy patients who underwent SMILE surgery. Participants were evaluated at baseline and three months after surgery. Preoperative accommodation assessment was performed while patients wore their contact lenses to correct their refractive error and neutralize any potential accommodative problems corresponding to a shift from a correction in the spectacle plane to the corneal plane.
Post-SMILE, the study found the amplitude of accommodation change wasn’t statistically significantly (mean difference: -0.24D). Additionally, accommodative responses measured at 0.00D, 0.50D, 1.25D, 2.00D, 3.00D and 4.00D didn’t markedly change. The accommodative facility was also unchanged with a mean difference of 1.11 cycles per minute, and no clinically significant associations between changes in accommodation and HOAs were noted.
The refractive and VA outcomes in the study agreed well with other investigations on SMILE for high myopia, the researchers said. The methodology in the current study, however, was slightly different since refractive errors were corrected with contact lenses to the greatest extent possible at both visits, which removed any influence from spectacles vs. contact lenses and any residual refraction on the assessment of accommodation, the investigators said.
Based on these results, patients with high myopia don’t need to be informed about any particular risks for reduced accommodation due to SMILE per se, but individuals should, especially if they have high myopia, be informed about the extra accommodative effort needed when changing correction from the spectacle plane to the corneal plane, the researchers explained.
Gyldenkerne A, Aagaard N, Jakobsen M, et al. Changes in accommodative function following small-incision lenticule extraction for high myopia. PLoS One. 2020;15(12): e0244602.