VDT work has increased rapidly in recent years, coupled with rises in screen time due to extensive smart phone use, with the loss of visual acuity an associated effect.
Therefore, researchers from BGG Japan and China undertook a randomised, placebo-controlled study in 60 healthy adults.
They were all aged between 20 years and 64 years of age, regularly performed VDT work, and had a high risk of eye fatigue.
Participants received a capsule containing AstaZine astaxanthin (9 mg/day) or placebo for 6 weeks.
Visual acuity, functional visual acuity, and pupil constriction rate were measured before and after visual display terminal work.
In subjects over 40 years of age, visual acuity of the dominant eye after VDT work demonstrated a stronger protective effect in the astaxanthin group versus the placebo group, suggesting that astaxanthin reduces the oxidative stress caused by such work.
Writing in the Journal of Clinical Biochemistry and Nutrition, the researchers reported: “In individuals aged 40 years and older, the actual measurement value and changes in visual acuity of the dominant eye (corrected) after VDT work at 6 weeks after intake showed significant difference between the astaxanthin and placebo groups.
“The gradual progression of hyperopia, which is known as presbyopia, begins in the 40s. This is due to age-related reduction in the regulation of ciliary muscle. Prolonged near work, such as VDT work, is a significant burden on vision (eg focusing ability). This may explain the positive effects of astaxanthin as shown in the stratified analysis of participants aged 40 years and older,” they added.
Blood flow
Previous studies have found that astaxanthin increases peripapillary blood flow, suggesting that it prevents reduction in visual acuity by maintaining blood flow.
In addition, other studies of the effects of astaxanthin on visual acuity also showed significantly improved visual acuity of the dominant eye (corrected).
“This is the second publication for visual health which used AstaZine,” said Dr Yanmei Li, BGG’s Global Chief Scientific Officer.
“As we age, doctors believe that key muscles in our eyes lose strength which, in turn, leads to a reduction in our ability to see detail. This is particularly pronounced in people overusing computers and smartphones.”
The researchers noted the study had several limitations.
Since a questionnaire survey of genetic and environmental factors in subjects with low uncorrected visual acuity was not included in this study, it was not possible to examine factors that improved visual acuity except for the pupil constriction rate.
Tests for presbyopia and astigmatism in these subjects were also not performed, so it was not possible to evaluate their effects on visual acuity after VDT work.
“Therefore, the mechanisms of the effects of astaxanthin on the prevention of a temporary loss of visual acuity are unknown. Future studies should examine the issue,” they added.
Source: Journal of Clinical Biochemistry and Nutrition
18 October 2022:1-8.
“Effects of diet containing astaxanthin on visual function in healthy individuals: a randomized, double-blind, placebo-controlled parallel study.”
Authors:Sekikawa, T, et al