薬理と治療

Abstract

Background Unfavorable changes in visual function due to visual display terminal（VDT） light exposures has become an increasing health problem. In this human study, we used a newly developed dietary supplement containing water chestnut extract（WCE）and lutein as potentially active ingredients（WCE-L diet）, and examined its effects on quantified VDT workload-affected visual function. Methods A randomized, double-masked, placebo-controlled, parallel-group intervention study was conducted on 110 healthy middle-aged adults with visual fatigue complaints. Fifty-five each subjects were assigned to receive either WCE -L diet（in daily doses of 100 and 15 mg as WCE and lutein, respectively）or placebo for 12 weeks. To evaluate the effect on visual function, five ophthalmic parameters comprising near point of accommodation （NPA）, spherical and cylindrical lens values, and near and distant best corrected visual acuities（BCVAs）were measured before and after the quantified VDT workload at baseline and at weeks 4, 8, and 12 of intervention. Results WCE-L diet supplementation caused no intervention-related adverse event nor laboratory test abnormality over the intervention period. In the analysis on the whole study population（n＝110）, changes from baseline in values of VDT workload-affected distant BCVA were significantly increased in WCE-L group compared with placebo group at all the three examination time points, while such a significant effect of WCE-L diet was not seen for any other ophthalmic parameters. Further exploratory analyses conducted by using ANCOVA within a subgroup of subjects with relatively stable and VDT workload︱sensitive NPA（n＝60）, suggested a favorable effect of WCE-L diet on NPA. Conclusion WCE-L diet was well tolerated and was shown to have the beneficial effect on visual acuity-related eye function and the potential for improving accommodation.