A 12-week-long intake of bilberry extract (Vaccinium myrtillus L.) improved objective findings of ciliary muscle contraction of the eye: A randomized, double-blind, placebo-controlled, parallel-group comparison trial

Abstract

A 12-week-long randomized, double-blind, placebo-controlled, parallel-group comparison trial was conducted to determine the effects of long-term standardized bilberry extract (SBE) intake on tonic accommodation of ciliary muscle caused by visual display terminal (VDT) tasks. This study was compliant with the accordance with CONSORT 2010 statement. A total of 109 healthy adult men and women aged 20–60 years were recruited and randomized into SBE and placebo groups. The subjects in the SBE and placebo groups were administered 240 mg of SBE and placebo, respectively, once daily for 12 weeks. Tests were performed before and after VDT tasks at week 0, 4, 8, and 12; high-frequency component (HFC)-1 value was the evaluation outcome. Results showed that post-load HFC-1 values at weeks 8 and 12 were significantly improved in the SBE group than in the placebo group (p = 0.014 and 0.017, respectively). Regarding the difference between before and after the task load (ΔHFC-1), the values were significantly better in the SBE group than in the placebo group at week 4 and 12 (p = 0.018 and 0.049, respectively). This study shows that oral consumption of 240 mg SBE extract for 12 weeks relieves the tonic accommodation of the ciliary muscle caused by VDT tasks and near-vision tasks.