Corneal remodeling and spatial profiles following small incision lenticule extraction.

Abstract

To evaluate the three-dimensional corneal spatial profiles following small incision lenticule extraction (SMILE) based on corneal asphericity, thickness, and volume. Eighty-three eyes in 83 patients who underwent SMILE were examined before and 1 and 6months after surgery. The asphericity of the anterior and posterior corneal surfaces was analyzed. Corneal volume (CV) was measured in corneal regions measuring 3.0mm, 5.0mm, and 7.0mm in diameter. Mean corneal thickness (CT) values were acquired at the apex (0.0mm) and in four concentric radial zones from the apex (with diameters of 2.0, 4.0, 6.0, and 8.0mm). The mean anterior Q value increased from - 0.32 preoperatively to 0.67 at 1month and 0.62 at 6months postoperatively. The mean posterior Q value decreased from - 0.30 preoperatively to - 0.26 at 1month and to - 0.25 at 6months postoperatively. The CV increased by 0.05 ± 0.06mm3 (1.40%), 0.06 ± 0.11mm3 (0.83%), and 0.09 ± 0.17mm3 (0.73%) along the radial zones with respective diameters of 3.0mm, 5.0mm, and 7.0mm. The CT increased by 6.02 ± 6.48µm (1.36%) at the apex and then decreased with increasing distance from the center, i.e., to 5.52 ± 6.31µm (1.20%) at 2.0mm, 4.72 ± 6.55µm (0.92%) at 4.0mm, 4.47 ± 7.86µm (0.75%) at 6.0mm, and 4.86 ± 10.31µm (0.70%) at 8.0mm. No correlations were observed between changes in CV and CT and refractive fluctuation between 1month and 6months postoperatively. The corneal profile displayed a less oblate shift on the anterior surface; however, the posterior surface showed a slight backward shift during the postoperative period. The CV and CT steadily increased after surgery and mainly within the operative zones. Refraction remained stable postoperatively and was not affected by the corneal remodeling.