Effect of fermented bilberry extracts on visual outcomes in eyes with myopia: a prospective, randomized, placebo-controlled study.

PURPOSE

To investigate clinically the effects of yeast-fermented bilberry extract on visual outcomes in myopic eyes.

METHODS

In a prospective, randomized, placebo-controlled, cross-over study, we examined 30 eyes of 30 middle-aged healthy volunteers (mean age±standard deviation, 39.5±7.2 years) with myopia [manifest spherical equivalent, -2.40±1.88 diopters (D)], who were randomly assigned to 1 of 2 oral regimens: fermented bilberry extract (400 mg/day) or placebo. We quantitatively assessed visual acuity, refraction, pupil constriction rate, accommodation, and mesopic contrast sensitivity (CS), before and 1 month after treatment. Only the right eyes were tested. The amplitude of accommodation and CS were measured with an accommodometer (D'ACOMO; WOC) and a CS unit (VCTS-6500; Vistech), respectively. From the CS, the area under the log contrast sensitivity function (AULCSF) was calculated.

RESULTS

The mean amplitude of accommodation increased significantly, from 4.62±1.88 D before treatment, to 5.33±2.03 D after treatment in the study group (Wilcoxon signed-rank test, P=0.002). Moreover, the mesopic AULCSF was significantly increased, from 1.04±0.16 before, to 1.13±0.17 after, treatment (P=0.009). However, we found no significant changes in accommodation or AULCSF in the control group (P>0.05), or any significant changes in any other parameters in either group (P>0.05).

CONCLUSIONS

The present data show that fermented bilberry extract is effective in causing increases in subjective accommodation and in mesopic CS in myopic eyes.