In our previous report, we showed the effect of astaxanthin intake on VEGF level in the aqueous humor and the relationship between VEGF level and reactive oxygen species-related parameters and other relevant factors. VEGF level is associated with total hydroperoxide level, and a multivariate analysis identified sex as a secondary factor affecting these relationships. Here, we analyzed the effects of astaxanthin on the relationship between VEGF level and reactive oxygen species-related parameters by sex. Patients (16 males and 19 females, aged 71.3 and 70.6, respectively) underwent bilateral cataract surgery on one side before and the other side after astaxanthin treatment (6 mg/day for 2 weeks). Levels of VEGF, hydrogen peroxide, and total hydroperoxide, and O2 •- scavenging activity, were measured in the aqueous humor. In females only, VEGF level was negatively correlated with O2 •- scavenging activity before the astaxanthin intake (r = -0.6, p<0.01) and positively correlated with total hydroperoxide level before and after the astaxanthin intake (r = 0.7 and 0.8, respectively, p<0.01). In conclusion, astaxanthin appears to affect O2 •- scavenging activity in the aqueous humor in females, and is likely to be involved in the control of VEGF levels in the anterior eye.