PT  - JOURNAL ARTICLE
AU  - Zhou, Xueyi
AU  - Shang, Jianmin
AU  - Qin, Bing
AU  - Zhao, Yu
AU  - Zhou, Xingtao
TI  - Two-year observation of posterior corneal elevations after small incision lenticule extraction (SMILE) for myopia higher than −10 dioptres
AID  - 10.1136/bjophthalmol-2018-313498
DP  - 2020 Jan 01
TA  - British Journal of Ophthalmology
PG  - 142--148
VI  - 104
IP  - 1
4099  - http://bjo.bmj.com/content/104/1/142.short
4100  - http://bjo.bmj.com/content/104/1/142.full
SO  - Br J Ophthalmol2020 Jan 01; 104
AB  - Aim To investigate the change in posterior corneal elevations (PCEs) of eyes with extremely high myopia 2 years after small incision lenticule extraction (SMILE).Methods We evaluated 39 eyes of 39 patients with spherical equivalent higher than −10.00 dioptres (D). Using a Scheimpflug camera (Pentacam), we measured change in PCEs at 1 day, 3 months, 6 months and 2 years after SMILE. Another 34 eyes of 34 patients who underwent femtosecond laser-assisted in situ keratomileusis (FS-LASIK) were examined before, at 1 day and long-term after surgery as the control group. For each eye, elevations at central, thinnest, maximal points and 24 other predetermined points were measured.Results No significant forward displacements of PCEs were observed in both surgeries. The maximal but not significant forward displacement occurred around 3–6 months following SMILE, and all returned to original levels 6 months postoperatively except superior area. The peripheral area tended to displace backward, while the central area tended forwardly. In both procedures, elevations along horizontal meridians, inferior and temporal hemispheres were significantly higher than those along vertical meridians, superior and nasal hemispheres, respectively (p<0.05). Elevation on the 4 mm, 6 mm diameters at 1 day and on the 6 mm diameter and temporal hemisphere at long-term follow-up postoperatively were significantly higher in FS-LASIK than SMILE (p<0.05). Change in elevations on the 6 mm diameter circle correlated with residual bed thickness (p=0.047).Conclusions SMILE is a safe way to correct for myopia higher than −10 D, with PCEs remaining stable 2 years after surgery.