Computer Vision Syndrome (CVS) & Lutein & Zeaxanthin. Zealut-Dena. Vitaminized- Buy supplements online

BENEFITS OF ZEALUT-DENA (LUTEIN AND ZEAXANTHIN) IN SUBJECTS WITH COMPUTER VISION SYNDROME

According to a survey conducted more than a decade ago, more than half of the working population used computers at that time [1], and the proportion of people using various electronic screens for work and in everyday life is thought to be now close to 100% [2]. It has long been recognized that prolonged use of electronic screens results in a variety of visual symptoms in a considerable proportion of users (56%, range 25%–93%, according to a review of nine studies published between 1974 and 19933, or 64–90% according to a more recent review [2]). The reported symptoms include eyestrain, headaches, ocular discomfort, dry eye, diplopia (double vision) and blurred vision. Taken together, these symptoms are referred to as computer vision syndrome (CVS). Some authors consider CVS to be synonymous with asthenopia [4], whereas others consider asthenopia synonymous with eyestrain and thus one of the symptoms of CVS. Regardless of the definition, eye- strain (or asthenopia in the narrow sense) is the main parameter used to quantitate the prevalence of CVS [5].

 

Although computer screens do not emit the particularly damaging UV light, they do emit blue light, which is also damaging to the retina [6] and might be one of the factors in CVS development. In particular, light emitted by light-emitting diodes (LED), which are used in recent models of computer monitors, has been found to be damaging to the retina, presumably because of oxidative stress from reactive oxygen species this light generates [7].

 

The carotenoids lutein and zeaxanthin are thought to have a dual protective effect: they filter out the most damaging irradiation (blue light and UV), and they scavenge reactive oxygen species. Although most lutein and zeaxanthin in the eye is concentrated in the retina (especially in the macula), they are the only carotenoid species present in the lens [8, 9]. Multiple carotenoid species are present in blood plasma, but only lutein and zeaxanthin are able to cross the hemato-ophthalmic barrier and accumulate in the eye tissues, including the retina, where their concentration is four orders of magnitude higher than in the blood [10, 11]. Dietary supplementation is an efficient way to increase the content of these carotenoids in the eye, especially in individuals with poor diet who receive insufficient amounts of lutein and zeaxanthin with food, as concluded by AREDS2, a large multicenter study conducted in 2006–2012 [12, 13]. The content of lutein and zeaxanthin in the eye tissues follows changes in the dietary intake of these carotenoids with a delay of two to three weeks [14]. The data from several studies shed light on the potential ability of lutein and zeaxanthin supplementation to alleviate CVS symptoms.

 

Circumstantial evidence comes from a study conducted in Finland, which reported a beneficial effect of sea buckthorn oil in individuals with dry eye [15], which is one of the CVS symptoms. This natural product contains zeaxanthin, among other ingredients, however the effects of individual ingredients have not been investigated.

 

A small-scale (13 participants) randomized, double-blind, placebo-controlled study conducted in Japan assessed the effects of a supplement containing lutein and zeaxanthin (5 mg and 1 mg, respectively, i.e. the amounts corresponding to half of a Zealut-Dena capsule) and blackcurrant extract (200 mg) [16]. The supplement or a placebo was given to the participants for two weeks, followed by two weeks of washout and then by two more weeks of the opposite treatment. Eye fatigue was measured by using subjective fatigue and stress scores as well as objective approaches such as electroencephalography, electrooculography and measuring the eye fixation-related potential. The study found significant differences between the supplement and placebo and concluded that the tested supplement can be used to reduce the symptoms of visual fatigue [16]. Notably, the observed effects were quite rapid in comparison with the beneficial effects of lutein and zeaxanthin in patients with such eye diseases as retinitis pigmentosa [17], diabetic retinopathy [18] or age-related macular degeneration [19]. A limitation of this trial was that the contributions of individual components (i.e., lutein, zeaxanthin and blackcurrant extract) were not tested.

 

The positive effect of lutein was ascertained by a study by Ma and co-workers [20], which involved 37 relatively young (22–30 years old) healthy participants who had been using computers for >10h a day over the previous two years. The participants were given either placebo or lutein (6 or 12 mg daily) for 12 weeks. The study found a significant and dose-dependent improvement in contrast sensitivity in the lutein groups. A slight improvement in visual acuity in both lutein groups was also observed, although this effect did not reach statistical significance.

 

Overall, although information on the benefits of lutein and zeaxanthin supplementation for CVS sufferers is so far limited and more detailed studies need to be conducted, the data available to date indicate that these carotenoids (or at least lutein) alleviate the CVS symptoms. As average dietary consumption of lutein plus zeaxanthin in the USA is estimated at only 1.7 mg/day, American Optometric Association currently recommends taking supplements that increase the intake to >6  mg/day [21]. In this respect, taking even one capsule of Zealut-Dena daily (i.e., 11 mg lutein plus zeaxanthin) is expected to be sufficient to mitigate any deficit of lutein and zeaxanthin intake with food. It should be also noted that the safety of long-term lutein and zeaxanthin supplementation has been confirmed [22, 23].

 

References

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  2. Rosenfield, M. Computer vision syndrome: a review of ocular causes and potential treatments. Ophthalmic Physiol Opt 31, 502-515 (2011).
  3. Thomson, W.D. Eye problems and visual display terminals--the facts and the fallacies. Ophthalmic Physiol Opt 18, 111-119 (1998).
  4. Ostrovsky, A., Ribak, J., Pereg, A. & Gaton, D. Effects of job-related stress and burnout on asthenopia among high-tech workers. Ergonomics 55, 854-862 (2012).
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  6. Youssef, P.N., Sheibani, N. & Albert, D.M. Retinal light toxicity. Eye (Lond) 25, 1-14 (2011).
  7. Lougheed, T. Hidden blue hazard? Environ Health Perspect 122, A81 (2014).
  8. Bernstein, P.S. et al. Identification and quantitation of carotenoids and their metabolites in the tissues of the human eye. Exp Eye Res 72, 215-223 (2001).
  9. Yeum, K.J., Shang, F.M., Schalch, W.M., Russell, R.M. & Taylor, A. Fat-soluble nutrient concentrations in different layers of human cataractous lens. Curr Eye Res 19, 502-505 (1999).
  10. Stringham, J.M. & Hammond, B.R., Jr. Dietary lutein and zeaxanthin: possible effects on visual function. Nutr Rev 63, 59-64 (2005).
  11. Whitehead, A.J., Mares, J.A. & Danis, R.P. Macular pigment: a review of current knowledge. Arch Ophthalmol 124, 1038-1045 (2006).
  12. Andreatta, W. & El-Sherbiny, S. Evidence-based nutritional advice for patients affected by age-related macular degeneration. Ophthalmologica 231, 185-190 (2014).
  13. Pinazo-Duran, M.D. et al. Do nutritional supplements have a role in age macular degeneration prevention? J Ophthalmol 2014, 901686 (2014).
  14. Loughman, J., Nolan, J.M. & Beatty, S. Impact of dietary carotenoid deprivation on macular pigment and serum concentrations of lutein and zeaxanthin. Br J Nutr 108, 2102-2103 (2012).
  15. Larmo, P.S. et al. Oral sea buckthorn oil attenuates tear film osmolarity and symptoms in individuals with dry eye. J Nutr 140, 1462-1468 (2010).
  16. Yagi, A. et al. The effect of lutein supplementation on visual fatigue: a psychophysiological analysis. Appl Ergon 40, 1047-1054 (2009).
  17. Dagnelie, G., Zorge, I.S. & McDonald, T.M. Lutein improves visual function in some patients with retinal degeneration: a pilot study via the Internet. Optometry 71, 147-164 (2000).
  18. Hu, B.J., Hu, Y.N., Lin, S., Ma, W.J. & Li, X.R. Application of Lutein and Zeaxanthin in nonproliferative diabetic retinopathy. Int J Ophthalmol 4, 303-306 (2011).
  19. Ma, L. et al. Effect of lutein and zeaxanthin on macular pigment and visual function in patients with early age-related macular degeneration. Ophthalmology 119, 2290-2297 (2012).
  20. Ma, L. et al. A 12-week lutein supplementation improves visual function in Chinese people with long-term computer display light exposure. Br J Nutr 102, 186-190 (2009).
  21. American Optometric Association. Lutein and Zeaxanthin - Eye-Friendly Nutrients. http://www.aoa.org/patients-and-public/caring-for-your-vision/nutrition/lutein-and-zeaxanthin?sso=y
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  23. Berson, E.L. et al. Clinical trial of lutein in patients with retinitis pigmentosa receiving vitamin A. Arch Ophthalmol 128, 403-411 (2010).