Effect of Femtosecond Laser in Situ Keratomileusis on the Choriocapillaris Perfusion and Choroidal Thickness in Myopic Patients

Abstract

ABSTRACT Purpose To investigate changes in choriocapillaris vascular density (CCD) and choroidal thickness (CT) after femtosecond laser in situ keratomileusis (FS-LASIK) in myopic patients. Methods Prospective and observational self-control study. We enrolled 41 myopic patients (41 right eyes), without other ophthalmic or systemic diseases who were eligible and about to FS-LASIK surgery. The CCD was measured in the central 1-mm-diameter circle region of the macular fovea (CCD1) and the 1- to 3-mm ring-like region of the fovea (CCD1-3). The CT was measured at the fovea and at distances of 0.5 and 2.5 mm for the following: nasal, temporal, superior, and inferior to the fovea. Both were measured by optical coherence tomography angiography (OCTA) preoperatively as the baseline and at 1 day, 1 week, 1 month, and 3 months postoperatively. Results CCD1 and CCD1-3 were significantly lower postoperatively compared with baseline. When the trough was reached, CCD1 declined by 1.51%, and CCD1-3 declined by 1.00% at 1 day postoperatively. However, then they increased with time. CCD1 recovered to baseline at 1 month postoperatively, while CCD1-3 was still lower at the end of follow-up. In addition, the CT was significantly thicker postoperatively and recovered to the baseline at 3 months postoperatively. There was no obvious correlation between CCD, CT, and other parameters. Conclusions The CCD decreased while the CT increased following FS-LASIK in myopic patients. However, these changes may be a temporary stress response rather than real irreversible injury to the choroid.