薬理と治療

Abstract

Objective In recent years, the ingestion of bilberry extract has been reported to improve visual function. However, there are insufficient clinical studies on the efficacy of bilberry extract for the improvement of visual display terminals（VDT）-induced eye fatigue. Therefore, we examined the safety and efficacy of bilberry extrac（t BILBERON(R)）on VDT-induced eye fatigue and eye dryness. Methods In this human trial, healthy adult subjects with subjective eyestrain who were exposed to VDT work for over 4h╱day were recruited. The subjects were randomly divided into 2 groups（n＝11╱group）and ingested either 120 mg╱day BILBERON(R) or placebo capsule orally for 6 weeks. VDT was loaded at the examination days of the before and after 6-week ingestion. Schirmerʼs test was performed before VDT load to assess eye dryness, and the following investigations were performed before and after VDT load: miosis frequency, near point pupil diameter（NPD）, and far point pupil diameter examination to determine accommodative function, critical flicker frequency（CFF）to assess eye fatigue, and a Likert scale questionnaire for subjective symptoms. Results Significant improvements were observed in amount of tears, NPD, and eye fatigue sensation in the test product group, as compared to those in the placebo group, after the 6-week ingestion period. Moreover, a measure of eye fatigue（CFF at red light）showed a significant decrease in the placebo group, as compared to those in the test product group, indicating a suppression of the accumulative eye fatigue in the test product group. Discussion Healthy subjects with subjective eyestrain showed improvements in VDT-induced eye dryness, accommodative function, eye fatigue and eye fatigue sensation following ingestion of 120 mg╱day bilberry extract（BILBERON(R)）for 6 weeks. In addition, the test product appeared to be safe under the conditions employed in the present study.