Our Defense Against Blue Light

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The eye is one of the most vital sensory organs in the entire body. It’s easy to take for granted the ability to see, especially with medical advances providing glasses, contact lenses and other ways to correct poor vision and maintain a quality of life. However, we should be aware of how vulnerable the eyes are and take special protective care. One important way to do this is by supplementing diet with nutrients that pay special attention to eye health.

The Digital Age and Its Shortcomings
In this technological age of computers, smart phones and tablets, our eyes are consistently exposed to blue light emitted from electronic screens. Digital eye strain is another issue and stems from an increasing reliance on devices and computers for work and leisure. About 60% of Americans use devices for upwards of five hours daily. Long periods of time spent on the phone or computer can cause irritated, dry eyes as well as a myriad of underlying issues (1). Retinal damage, poor glare recovery and age-related eye conditions are very real. Children are particularly vulnerable because their eyes are underdeveloped, but their use of tablets and smart phones is pervasive. The use of devices before bed also has negative consequences because it throws the biological clock or circadian rhythm (2).

The main problem is blue light overexposure. Of all the light on the visible spectrum, blue light is the most harmful to our eyes. It penetrates deep into the eye, damaging photoreceptors and jeopardizing long-term eye health. It can cause short term effects like headache, eye fatigue or blurred vision. Long-term effects include retinal damage, lowered quality of vision or even poor sleep habits. Unfortunately, blue light is everywhere and can come from computer screens, artificial light and even sunlight, which makes it unavoidable. Things like TVs and tablets are responsible for a significant amount of blue light exposure. Though this is the case, there are things we can do to protect our eyes and maintain eye health now and in the future.

How Blue Light Harms the Eyes
Light, a form of electromagnetic energy, is absorbed constantly by photoreceptors in the eye. There are three wavelengths that come into contact with the eye: ultraviolet, visible light and infrared. Visible light is referred to as short (blue), medium (green), and long wavelength (red). When light travels from its source to our retinas it travels by way of optical tissue. The light that does not go directly into the central retina is most likely absorbed or scattered by this tissue. This depends on the wavelength of the light that is being perceived. The light that is absorbed determines how much damage is caused to the retina. Other factors that play into the damage of the tissue and retina include direction of gaze, lens characteristics, duration of direct light transmission through the pupil, iris pigmentation and pupil diameter (3).

All light gets filtered through our eyes, and there are three ways light can adversely affect the eye: photothermal, photomechanical, and photochemical. Photothermal damage has to do with radiation. Light photons sometimes come with more radiant energy than the retinal tissue is equipped to handle. When light with high radiant energy is absorbed into the eye it raises the molecular energy in the eye’s tissue making the molecules move around more and collide with each other. This is what causes the damage. The amount of radiation in a source of light (such as blue light) — the amount of damage it is capable of — is determined by its wavelength. Generally speaking, the shorter the wavelength, the greater increase in molecular movement and the greater the rise in temperature. Rising temperature in the eye causes all types of molecular and cellular damage. Photomechanical damage happens when there is more radiation present in the eye than the eye is able to recover from. And photochemical damage is caused by exposure to high-intensity light whether it be a short burst of light or exposure to intense light over a longer period of time (3).

LED lights are the most common source of artificial light. They are more powerful than regular incandescent lights and are used in almost every electronic device. Prolonged exposure to LED light further increases the potential production of reactive oxygen species (ROS); thus, the oxidative damage can lead to the accumulation and build-up of lipofuscin in the retinal pigment epithelium (RPE). The build-up of lipofuscin in the RPE can affect the ability of the RPE to provide nutrients to the photoreceptors, affecting photoreceptor viability. Moreover, when lipofuscin absorbs blue light, the material becomes phototoxic, which can lead to further damage in the RPE and in the photoreceptors (4).

Aging Eyes
Eye health problems are more likely to happen the older a person gets. Cataracts and age-related macular degeneration (AMD) are two very common eye conditions in older adults. Cataracts are the clouding of the eye lens. Over time, if not treated, it will become more and more difficult to see through that cloud. It causes colors to appear dull and glare to be harder to recover from. Cataracts are the leading cause of blindness and affect half of Americans over age 80 with increased risk if the person is diabetic.

Another problem that affects most people in their later years is macular degeneration. AMD breaks down sharp central vision. There are two types of AMD: wet and dry. Wet AMD happens when blood vessels grow under the macula and leak blood. This type of AMD damages the eye more quickly. Dry AMD deteriorates light-sensitive cells in the eye. Lutein and zeaxanthin supplementation can help reduce the risk of AMD by neutralizing free radicals that cause harmful oxidation of the eye lens. The lutein and zeaxanthin present in the eye can also absorb light and offer protection from its harmful effects. Studies like the Blue Mountains Eye Study found that patients with the highest level of dietary lutein and zeaxanthin intake were less likely to have incidents of AMD. The study featured over 2,000 people ages 50 and up in the Blue Mountains of Australia. The participants were given a variety of carotenoids including lutein and zeaxanthin. Beta carotene and vitamin A were also found to help fight against cataracts (5).

Nutritional Support
Vitamin A, along with being very beneficial to the immune system and bone growth, plays a big part in eye health as well. It protects the surface of the eye — the cornea which is essential for good vision — and strengthens its barrier against infection. Vitamin A from animal products, or retinal, is more readily used by the body, while vitamin A from fruits or vegetables is turned into retinol later on in digestion (6).

When it comes to harmful blue light, the eye protects itself with the macular pigment in the back of the eye. The macular pigment is a yellow spot that can partially or completely filter blue light. The density of the macular pigment is indicative of how much protection against blue light is present. The macular pigment is made up primarily of two carotenoids — lutein and zeaxanthin. When these nutrients are consumed they go directly into the eye where it can help macular pigment do its job. They are not naturally occurring in the body but come from certain foods we eat and carotenoid supplements. Lutein and zeaxanthin are most abundant in dark green veggies as well as yellow and orange fruits.

Have you ever wondered what gives a cantaloupe its orange shade or a red bell pepper its vibrant color? This is the work of carotenoids, a pigmented substance found in all kinds of fruits and vegetables. Squash, tomatoes, carrots, and oranges are just some of the foods high in carotenoids. In plants, carotenoids are responsible for light absorption necessary for photosynthesis. In the human body, carotenoids act as antioxidants. Some carotenoids like beta-carotene are highly desired because they can be converted easily into vitamin A in the body (7).

Unfortunately, the average person does not get enough lutein and zeaxanthin in their diet. Studies show that consuming 10 g of lutein and 2 g of zeaxanthin is the amount that best supports eye health. A person would have to consume three cups of raw spinach daily, which is the same as one lutein supplement daily. Therefore supplementation is the most convenient and practical way to achieve this recommended amount, though maintaining a diet rich with these nutrients is still ideal (1).

Along with supplements and a heathy diet, your customers should also take other steps to ensure the health of their eyes. Take frequent breaks when working on a computer. The most common is the 20-20-20 rule where every 20 minutes, you stare at something at least 20 feet away for at least 20 seconds. Though it may sound like common sense, blinking more to keep your eyes lubricated is very important. Visit the eye doctor at least once a year. Wear sunglasses on sunny days (8). Talk to an optometrist about blue light-filtering glasses or if you have any special conditions or questions. WF

References
1. Kemin Industries, Inc. “Floraglo Lutein,” https://www.kemin.com/en/north-america/products/floraglo-lutein/beat-the-blue, accessed June 25, 2017.
2. Harvard Health Letter. “Blue Light Has a Dark Side,” http://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side, accessed July 13, 2017.
3. P. N. Youssef, N. Sheibani and D. M. Albert. “Retinal Light Toxicity,” http://www.nature.com/eye/journal/v25/n1/full/eye2010149a.html#aff1, accessed July 13, 2017.
4. Gianluca Tosini, Ian Ferguson, and Kazuo Tsubota. “Effects of blue light on the circadian system and eye physiology,”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/, accessed July 13, 2017.
5. America Optomotric Association. “Cataract,” https://www.
aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/cataract?sso=y, accessed July 13, 2017.
6. Gary Heiting. “Vitamin A and Beta Carotene: Eye Benefits,” http://www.allaboutvision.com/nutrition/vitamin_a.htm, accessed July 21, 2017.
7. Jessie Szalay. “What are Carotenoids?” https://www.livescience.com/52487-carotenoids.html, accessed June 25, 2017.
8. Dr. Mathew Alpert, O.D. “How to Protect Your Eyes From the Negative Effects of Digital Devices and Blue Light,” http://www.huffingtonpost.com/dr-matthew-alpert-od/blue-light_b_5570433.html, accessed July 13, 2017.

Published in WholeFoods Magazine September 2017

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