Many studies demonstrate that exposure to sunlight provides protection to diseases such as hypertension, diabetes, multiple sclerosis, and a variety of cancers, and avoiding sunlight may influence their progression.1 It has been thought that these protections are due only to vitamin D, whose creation requires sunlight, but researchers are now reporting that circadian clock influencing, immune response modification, and nitric oxide, melatonin, and serotonin formation are involved as well.2 In fact, researchers are finding that the risk of skin cancer increases with irregular patterns of sun exposure, while regular patterns convey relatively lower risk. This is the difference between getting sunburned versus a brisk daily walk in the sunlight.
But too much sunlight is harmful to both eyes and skin. We know that getting sunburned increases skin cancer risk. Our vision is also directly negatively impacted by the sun and ultraviolet radiation (UVR), as well as blue light from computer screens.
Impacting the Delicate Structures of the Eye
Excessive radiation from sunlight, especially ultraviolet radiation (UVR) damages the retina, cornea, and lens.
Exposure to light of specific wavelengths or intensity may induce severe damage to the retina. Ongoing exposure to the sun without the protection of 100% UVA/UVB sunglasses can cause or contribute to a range of eye conditions,3 including macular degeneration,4 cataracts,5 and the onset of pterygium or pinguecula.6
Types of UV Radiation
UV radiation is divided into three distinct bands in order of decreasing wavelength and increasing energy: UVA (320-400 nm), UVB (290-320 nm), and UVC (200-290 nm). Different wavelengths and energy associated with UV subdivisions correspond to distinctly different effects on living tissue. Compared to UVB, UVA can penetrate deeper through the skin7 and is not filtered by window glass. It has been estimated that about 50% of exposure to UVA occurs in the shade. Blue light is part of the sunlight spectrum, and in some ways it is even more dangerous due to our extensive additional exposure from mobile devices, computers, tablets, and large LCD screens. Blue light prevails in red, green, blue (RGB), and SSL illumination systems that did not exist a decade ago.
The primary indicators that determine whether light from the sun (or other sources such as computer screens or LED light bulbs) will injure our eyes depends on three factors8
- Intensity means how bright the light is.9 More intense light (mid-day light) causes more damage. But the light at sunrise and sunset, known as near-infrared (NIR) may be helpful. In fact some researchers report that, “NIR might even precondition the skin from an evolutionary standpoint as exposure to early morning NIR wavelengths in sunlight may prepare the skin for upcoming mid-day harmful UVR.”10
- Wavelength (energy). UVR (especially UVA, with the shortest wavelength and greatest energy) transmits more energy than visible light and high dose exposure to UVR causes direct cellular damage. 11
- Age is an important factor. Children are especially vulnerable to UVR because of their larger pupils and more transparent cornea, aqueous liquid, lens and vitreous humour. Researchers report that up to 80% of a person’s lifetime exposure to UVR occurs before age 18.12
Types of Damage
This damage can be thermal, causing corruption of protein structure in eye tissues (such as snow blindness), photomechanical (such as damage due to clinical use of laser light that pulses more rapidly than tissues can respond), or photochemical. Of the three types of photochemical damage, the two most common are oxidative and sensitization reactions, and they are caused by solar energy and especially UVR. This type of damage occurs when photoreceptor pigments, proteins, flavoproteins, and melanin and lipofuscin in the retinal pigmented layer are excited by UVA energy.
Protection: Conventional Approach
Wear 100% UVA/UVB sunglasses (preferably polarized) when outside. The best lens color is amber which neutralizes blue light. Yellow, copper, brown, and orange are better than green, grey, or blue. People who drive frequently find that brown and copper tinted lenses improve visual acuity and enhance recognition of red warning lights. When it is overcast or when hazy blue light is scattered, it decreases depth perception and visual acuity and contributes to eye fatigue. Yellow and amber lenses help neutralize the blue light and protect our eyes.
Avoid blue light from your computer. Using yellow tinted glasses when working on the computer or setting your computer display to a warm color helps protect against computer screen blue light.13 14
No to sunscreen pills. There are a number of companies marketing sunscreen pills. According to the NIH, these do not actually provide protection against sun exposure (they may offer some protection against cell damage and inflammation); Using sunscreen (SPF 30 or higher) when outside still offers the best protection. The FDA stated that the marketing campaigns for these pills is “putting people’s health at risk by giving consumers a false sense of security.”
No to LED lights. Researchers find that LED light causes retinal injury and oxidative damage, a loss of photoreceptors, and cell death in the retina.15
More Protection: Complementary Approach
Certain nutrients act as powerful antioxidants in the eyes and help filter out UV and blue light that cause oxidative damage.
Lutein, a powerful antioxidant, makes up the macular pigment in the retina and helps protect against damaging blue light.16 17
Zeaxanthin. Like lutein, zeaxanthin protects the eye from blue light that causes damage from oxidative stress.18
Vitamin C (buffered and ascorbated). As an antioxidant, vitamin C scavenges free radicals in the body and protects tissues from oxidative stress. 19
Astaxanthin. 6mg–12mg per day. Astaxanthin protects against damage from light due to its antioxidant effect.20
Additional herbs, vitamins and oils that have potent antioxidant properties, protect against sun damage, and potentially protect against skin cancer include curcumin, resveratrol, vitamin E, quercetin, milk thistle, green and black teas, walnuts, and borage, evening primrose, and avocado oils.21
For sunburns, tea tree oil applied to the skin can relieve sunburn by increasing blood flow in capillaries, bringing nutrients to damaging skin. Apply liquid from the underside of watermelon peels also helps
Important life-style points. In addition, pay attention to other important life-style recommendations to protect your vision.
Juicing recipe. We recommend some combination of the following fruits and vegetables to support skin health22 and help protect against the effects of UV light exposure:
- Green-leafy vegetables (including kale and turnip greens), grapes, cranberries, orange, kiwi, strawberries, pineapple, apples, figs, carrots, broccoli, cabbage, peppers (green, red and yellow), and walnuts.
- Razzaque MS. (2018). Sunlight exposure: Do health benefits outweigh harm? J Steroid Biochem Mol Biol. Jan;175:44-48.
- Van der Rhee HJ, de Vries E, Coebergh JW. (2016). Regular sun exposure benefits health. Med Hypotheses. Dec;97:34-37.
- Glickman RD. ( 2011). Ultraviolet phototoxicity to the retina. Eye Contact Lens. Jul;37(4):196-205.
- Roberts JE. (2011). Ultraviolet radiation as a risk factor for cataract and macular degeneration. Eye Contact Lens. Jul;37(4):246-9.
- Löfgren S. (2017). Solar ultraviolet radiation cataract. Exp Eye Res. Mar;156:112-116.
- Delic NC, Lyons JG, Di Girolamo N, Halliday GM. (2017). Damaging Effects of Ultraviolet Radiation on the Cornea. Photochem Photobiol. Jul;93(4):920-929.
- Wang PW, Hung YC, Lin TY, Fang JY, Yang PM, et al. (2019). Comparison of the Biological Impact of UVA and UVB upon the Skin with Functional Proteomics and Immunohistochemistry. Antioxidants (Basel). Nov 20;8(12):569.
- Ivanov IV, Mappes T, Schaupp P, Lappe C, Wahl S. (2018). Ultraviolet radiation oxidative stress affects eye health. J Biophotonics. Jul;11(7):e201700377.
- Haywood R, Andrady C, Kassouf N, Sheppard N. (2011). Intensity-dependent direct solar radiation- and UVA-induced radical damage to human skin and DNA, lipids and proteins. Photochem Photobiol. Jan-Feb;87(1):117-30.
- Barolet D. (2021). Near-Infrared Light and Skin: Why Intensity Matters. Curr Probl Dermatol. 2021;55:374-384.
- Ibid. Ivanov. (2018).
- Ibid. Ivanov. (2018).
- Blehm C, Vishnu S, Khattak A, Mitra S, Yee RW. (2005). Computer vision syndrome: A review. Surv Ophthalmol. May-Jun; 50(3):253-62
- Lee JB, Kim SH, Lee SC, Kim HG, Ahn HG, et al. (2014). Blue light-induced oxidative stress in human corneal epithelial cells: protective effects of ethanol extracts of various medicinal plant mixtures. Invest Ophthalmol Vis Sci. Jun 12; 55(7):4119-27. ↩
- Jaadane I, Boulenguez P, Chahory S, Carré S, Savoldelli M, et al. (2015). Retinal damage induced by commercial light emitting diodes (LEDs). Free Radic Biol Med. Jul; 84():373-384.
- Richer S, Stiles W, Statkute L, Pulido J, Frankowski J, et al. (2004). Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial). Optometry. Apr;75(4):216-30.
- Bernstein PS, Zhao DY, Wintch SW, Ermakov IV, McClane RW, et al. (2002). Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients. Ophthalmology. Oct;109(10):1780-7. ↩
- Bian Q, Gao S, Zhou J, Qin J, Taylor A, et al. (2012). Lutein and zeaxanthin supplementation reduce photooxidative damage and modulates the expression of inflammation-related genes in retinal pigment epithelial cells. Free Radic Biol Med. Sep 15;53(6):1298-307.
- Chew EY, Clemons TE, Agron E, Sperduto RE, Sangiovanni JP, et al. (2013). Long-term effects of vitamins C and E, β-carotene, and zinc on age-related macular degeneration: AREDS report no. 35. Opthalmology. Aug;120(8):1604-11.
- Otsuka T, Shimazawa M, Nakanishi T, Ohno Y, Inoue Y, et al. (2013). Protective effects of a dietary carotenoid, astaxanthin, against light-induced retinal damage. J Pharmacol Sci. 123(3):209-18.
- Souied EH, Delcourt C, Querques G, Bassols A, Merle B, et al. (2013). Oral docosahexaenoic acid in the prevention of exudative age-related macular degeneration: The Nutritional AMD Treatment 2 Study. Ophthalmology. Aug;120(8):1619-31.
- Korac RR, Khambholja KM. (2011). Potential of herbs in skin protection from ultraviolet radiation. Pharmacogn Rev. Jul-Dec;5(10):164-173.
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At Golden Eye Optometry, we view good vision care as front line protection at every age. A routine eye exam can detect more than poor vision. It can shed early light on glaucoma, macular degeneration, cataracts and diabetes.