“The major finding of the present study was that VDT operation temporarily impaired the eye–hand coordination and smooth-pursuit eye movements, and astaxanthin, lutein and zeaxanthin improved eye–hand coordination impaired by VDT operation,” wrote the team of Japanese researchers.
The study, published in the journal Nutrients, was supported by Senju Pharmaceuticals and evaluated an astaxanthin, lutein and zeaxanthin combination provided by natural ingredients supplier BGG World.
Countering the effects of the video display terminal
Prolonged VDT use has been associated with reduced blinking frequency and increased tear evaporation, leading to dry eye and associated symptoms including ocular discomfort, fatigue and blurred vision.
“VDT operation has been reported to lead to continuous tension of the ciliary muscle because the time spent looking closely at a terminal is long, leading to a decrease in the amplitude of accommodation,” the Japanese research team noted. “In addition, VDT operation induces a decline in oculomotor function through extraocular muscle strain. Therefore, we theorize that temporary eye–hand coordination and smooth-pursuit eye movement impaired by VDT operation may be attributed to a decline in accommodation and oculomotor function.”
In presenting their line of study, the researchers reference findings that astaxanthin (derived from Haematococcus pluvialis microalgae) improves accommodative, oculomotor and physical functions and note that lutein and zeaxanthin (most often found in green leafy vegetables and most potent in marigold flowers) accumulate in the macular pigment to absorb the blue light exposure emanating from VDTs and increase visual processing speed and contrast sensitivity.
The randomized, double-blind, placebo-controlled study recruited healthy Japanese males and females between the ages of 20 and 60 years who routinely played video games, used computers or performed VDT activities. Participants were assigned to either a test group consuming 6 mg astaxanthin, 10 mg lutein and 2 mg zeaxanthin (66 mg/capsule: Hematococcus-pluvialis-derived pigment and 55 mg/capsule: marigold supplied by BGG Japan Co., Ltd.) or a rice oil placebo once a day for eight weeks.
The researchers evaluated eye–hand coordination, smooth-pursuit eye movements and macular pigment optical density (MPOD) at 0, two, four and eight weeks after soft-capsule intake. Primary outcomes were visual functions (eye–hand coordination time and accuracy rate and visual motion reaction time through smooth-pursuit eye movement).
“The active group showed significantly improved eye–hand coordination after VDT operation at eight weeks,” the study concluded. “However, there was no clear improvement in the effect of the supplementation on smooth-pursuit eye movements. The active group also showed a significant increase in MPOD levels.”
Limitations noted included not controlling for astaxanthin, lutein and zeaxanthin in daily diet and uncertainty as to whether the benefits could be attributed to an additive or synergistic effect.
“Although we believe that the combination of these nutrients is essential for the effects on eye–hand coordination because of the different mechanisms of action between astaxanthin and lutein/zeaxanthin, further studies are necessary to clarify the mechanisms underlying the beneficial effects of these nutrients,” the researchers noted.
Expanding eye health benefits
BGG World, which provided the supplement ingredients for the study, has carried out its own research to substantiate the benefits of its ingredients for different aspects of eye health.
“Previous two studies (one on AstaZine alone, the other on AstaZine+MyrtiPro+lutein) were focused on visual functions pre- and post-VDT work (acuity, pupillary adjustment, BUT, etc.), whilst this study examined effect on eye-hand coordination which is related to accommodative, oculomotor and physical functions, rather than visual functions,” Shaheen Majeed, CEO at BGG Americas and Algae Health Sciences, told NutraIngredients-USA.
He added that there could be future interest in conducting combination studies in the eye care segment not limited to lutein/zeaxanthin with a view to introducing a new synergistic combination with clinically supported ingredients.
“Effects of Astaxanthin, Lutein, and Zeaxanthin on Eye–Hand Coordination and Smooth-Pursuit Eye Movement after Visual Display Terminal Operation in Healthy Subjects: A Randomized, Double-Blind Placebo-Controlled Intergroup Trial”
Authors: Keisuke Yoshida et al.