摘要： Purpose: To compare visual acuity and intraocular straylight after implantation of clear and photochromic intraocular lenses (IOLs) in a mesopic lighting condition. Methods: Clear IOLs were implanted in 95 eyes of 72 patients (clear IOL group), and photochromic IOLs were implanted in 22 eyes of 16 patients (photochromic IOL group). Best-corrected visual acuity (BCVA) was measured indoors before surgery and 1 month after surgery. Straylight values were measured indoors before surgery and 1 and 2 months after surgery using the C-quant straylight meter (Oculus GmbH, Wetzlar, Germany). Results: There were no significant differences between the 2 groups in BCVA at 1 month postoperatively (p = 0.587). Mean straylight values of clear and photochromic IOL groups were 2.76 ± 1.89 log (s) and 2.88 ± 2.04 log (s) preoperatively, 1.39 ± 0.84 log (s) and 1.32 ± 0.26 log (s) at 1 month postoperatively, and 1.43 ± 0.92 log (s) and 1.45 ± 0.50 log (s) at 2 months postoperatively. There were no significant differences between the 2 groups in indoor straylight values (p = 0.778, 0.709, 0.929, before surgery, 1 and 2 months after surgery respectively). Repeated-measure analysis of straylight values also showed no significant difference between the 2 groups (p > 0.05). Conclusions: There were no significant differences in BCVA and straylight values between clear and photochromic IOL groups under a mesopic light condition. Therefore, photochromic IOL could be suitable choice for cataract patients who spend significant time under mesopic conditions.