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.
Keywords: Choriocapillaris perfusion; Choroidal thickness; FS-LASIK; myopic; vascular density.