Study shows stability of posterior maximum elevation after SMILE

A prospective study found that long-term changes in posterior maximum elevation do not occur after small incision lenticule extraction.

Thirty-six eyes of 20 patients with mean preoperative myopia of –6.24 D underwent SMILE without complications. The same surgeon performed all the procedures using the VisuMax femtosecond laser system (Carl Zeiss Meditec).

The posterior corneal surfaces were measured using the Pentacam (Oculus) preoperatively and at 1 month, 6 months, 1 year, 2 years and 3 years postoperatively. The data analyzed were posterior central elevation (PCE), posterior maximum elevation (PME) and posterior elevation at the thinnest corneal point (PTE) in the central 4-mm area above the best-fit sphere.

There was no statistically significant changes in PME at 3 years after SMILE. There were statistically significant differences in PCE and PTE, but the changes were on the negative side, suggesting that no forward displacement of the central posterior corneal surface occurs. No correlation between residual bed thickness and changes in posterior elevation was found.

“The cause of the slight backward tendency in the central posterior corneal surface should be explored in the future; data of the posterior elevation in the peripheral area are also required to provide more insights into the morphological changes of the cornea in eyes after SMILE,” the authors said. – by Michela Cimberle

Disclosure: The authors report no relevant financial disclosures.

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Source:

Zhao Y, et al. J Refract Surg. 2017;doi:10.3928/1081597X-20161117-0 1.