By Dr. Mercola
Just as a natural, non-toxic sunscreen can be beneficial when you're going to be exposed to excessive amounts of sunlight, sunglasses, too, have their place.
If you're downhill skiing or out on the water, sunglasses can help to shield your eyes from sun damage… however, I don't personally wear them for many occasions other than this, for reasons I'll explain shortly.
That said, too much sun can potentially damage the skin around your eyes, your lens and increase your risk of cataracts. So when choosing sunglasses, it's important to know what qualities to look for.
How Can the Sun Damage Your Eyes?
Just like your skin, your eyes are susceptible to damage from too much sun exposure. The skin around your eyes, including your eyelids, is among the thinnest and most sensitive on your body, making it particularly vulnerable to wrinkling and age spots from excessive exposure to ultraviolet (UV) rays.
However, even your eyes themselves can be damaged by too much sun:1
- The white of your eye: Sun damage may cause the conjunctiva, the thin membrane covering the white of your eye, to thicken and become irritated and inflamed. If the conjunctiva thickens and grows over your cornea (called pterygium or 'surfer's eye'), it can interfere with your vision.
- Retina: If the macula, a part of your retina, deteriorates, it can lead to macular degeneration, a leading cause of blindness. There is some evidence of a link between macular degeneration and exposure to UV light. Astaxanthin is also useful here, as it has been shown to prevent and treat age-related macular degeneration.
- Iris: If you have blue eyes, you may be more susceptible to UV-induced eye damage, including macular degeneration.
- Lens: UV light may lead to the development of certain types of cataracts, which is a cloudiness on the lens of your eye that can also interfere with your vision.
- Cornea: Your cornea can become acutely sunburned, causing serious pain and temporary blindness. Chronic excessive exposure can lead to cataracts, especially if you have a poor diet with low antioxidants.
Keep in mind, too, that certain medications can increase your eye's sensitivity to the sun. This includes drugs such as birth control pills, diuretics, tranquilizers, tetracycline and sulfa drugs.
What Should You Look for in a Pair of Sunglasses?
For the times when you need serious sun protection for your eyes, not all sunglasses are created equal. You can't use price as a gauge of quality, either, as many of the higher priced brands cost more because of fashion, not function. Some quick tips to ensure you're getting a high-quality pair include:
- Avoid sunglasses that simply say "absorbs UV," instead look for a label that says 99-100 percent UV absorption or UV 400 (which means they block all UVA and UVB rays)
- Polarized lenses help cut glare allowing for crisper vision, but they do not add sun protection
- Darker lens colors don't necessarily mean better sun protection, as the UV protectant added to lenses is clear; even gray, green, yellow or rose lenses can offer adequate UV protection
- Sunglasses made from pressed plastic will lead to distorted vision when you look to the right or left; choose sunglasses with optically ground lenses for less distortion
- Larger frames and wraparound styles will shield more UV rays than smaller styles, as will close fitting glasses
The infographic below, from The Huffington Post, sums up this information nicely:2
Be Careful of 'Sunglasses' Called 'Eyeware' or 'Sunware'
If you purchase a pair of sunglasses, they must offer some level of UV protection. This level could vary, however, which is why it's best to look for those that specify a certain level, such as UV 400 or 100 percent UV absorption, as mentioned. Because the US Food and Drug Administration (FDA) only regulates whether companies adhere to the labeling, if your sunglasses claim to be "100 percent UV protected," they must live up to that claim.
That said, there are other types of glasses on the market that are marketed as sunglasses but are actually called:
- Sun blockers
- Polarized glasses
In these cases, they may offer no UV protection at all, yet would still be allowed under the FDA rules because they're not technically called 'sunglasses.' There are also so-called 'cosmetic' sunglasses, which typically block only about 70 percent of UV rays.
Again, remember that price is not an indicator of quality sun protection. CBS News actually did a study comparing cheap sunglasses ($5 a pair) to high-end brands like Versace ($200 a pair). All 31 pairs carried claims that they offered excellent UV protection… and all but one (a cheap pair) actually did.3 In other words, if your sunglasses claim to offer good UV protection, they probably do. But, if you're uncertain, take them in to an eye center. Most will test the UV protection level of your sunglasses for free, and it takes less than 30 seconds to do so.
Why I Rarely Wear Sunglasses
As I mentioned, I only wear sunglasses on rare occasions, such as when I'm downhill skiing or, sometimes, if I'm boating on the water. Under these conditions, the snow or water greatly magnifies the sunlight, which could potentially be harmful, especially after hours of exposure.
On an average sunny day, however, wearing sunglasses is the last thing you want to do for your vision health, because you will be blocking potentially beneficial wavelengths of light from reaching your eyes. There are actually more than 1,500 wavelengths of light that you need to nourish your eyes. So I avoid using sunglasses, because I believe your eyes need to receive the full spectrum of light to function optimally, and sunglasses block out some essential waves of the light spectrum.
Instead of sunglasses, I wear a lightweight cap with a visor like this one to protect my face and eyes from direct sunlight. This is typically all that is needed and will still allow your eyes to benefit from the full spectrum of light. My team liked the cap that I wear so much that we even offer it for sale in our store.
Your Body Needs Exposure to Bright Light During the Day
There's another reason why you need to be careful about overly shielding your eyes from sunlight, and that is because when full-spectrum light enters your eyes, it not only goes to your visual centers enabling you to see, it also goes to your brain's hypothalamus where it impacts your entire body.
Your hypothalamus controls body temperature, hunger and thirst, water balance and blood pressure. Additionally, it controls your body's master gland, the pituitary, which secretes many essential hormones, including those that influence your mood. Exposure to full-spectrum lighting is actually one effective therapy used for treating depression, infection, and much more.
Studies have also shown that poor lighting in the workplace triggers headaches, stress, fatigue and strained watery eyes, not to mention inferior work production. Conversely, companies that have switched to full-spectrum lights report improved employee morale, greater productivity, reduced errors and decreased absenteeism. Some experts even believe that "malillumination" is to light what malnutrition is to food.
Your 'body clock' is also housed in tiny centers located in the hypothalamus, controlling your body's circadian rhythm. This light-sensitive rhythm is dependent on Mother Nature, with its natural cycles of light and darkness, to function optimally. Consequently, anything that disrupts these rhythms, like inadequate sunlight exposure to your body (including your eyes), has a far-reaching impact on your body's ability to function. The best way to get exposure to healthy full-spectrum light is to do it the way nature intended, by going out in the sun with your bare skin – and 'bare' eyes -- exposed on a regular basis.
Have You Heard of Sun Gazing?
Sun gazing originated in India more than 2,000 years ago, although it was also practiced by ancient Egyptians, Aztecs, Greeks, Mayans, in Tibetan Yoga and some traditions of Qigong, Tai Chi, and by some Native American tribes. Sun gazing -- also known as solar healing, solar gazing, sun staring, Sun Yoga, Surya Yoga and Solar Yoga -- refers to the practice of staring directly at the sun in order to receive nourishment, healing and spiritual enlightenment. The gazing is done only during the first hour after sunrise or the last hour before sunset, when the sun's rays are most gentle to your eye. If you perform it at other hours, you can cause serious damage to your retina.
It's interesting to note that your pineal gland (aptly named your "third eye" considering its anatomical location and the fact that it contains light-sensitive cells) is also activated by light. Light reaches it by passing into your eyes, then along a pathway from your retina to your hypothalamus called the retinohypothalamic tract, then along nerve pathways to your pineal gland.
Light impulses inhibit the production of melatonin, and at night when it is dark, pineal inhibition ceases, and melatonin is released. Therefore, the pineal gland is an important timekeeper for your body. Melatonin is also produced during visualization and relaxation. It's thought that the light energy you take in while sun gazing activates your dormant pineal gland, which then turns your "brainuter" on. It is this activation that causes you to experience the seemingly magical conversion of sun energy into nutrition, healing of disease, heightened energy, increased psychic abilities and, ultimately, enlightenment.
Sun gazing is highly controversial due to the considerable evidence, which states that looking directly at the sun can be damaging to your eyes. So while I am not advocating gazing into the sun directly, I think it's important to reflect on this phenomenon that is already occurring, and from which many have experienced benefits. If you'd like to learn more about sun gazing (which you should definitely do before attempting it), you can do so here.
Use Your Body as Your Sunglasses Guide
Remember, when you eat a high-quality nutritious diet, you load your body with magnificent antioxidant protection so the need for some of these issues becomes diminished the higher the quality of your diet is. You can also improve your protection by using targeted antioxidants, like astaxanthin, which is a carotenoid shown to prevent and treat age-related macular degeneration.
There's a lot we're still learning about the sun and how it influences human health… and, conversely, how the use of man-made sun-blocking devices like sunglasses may negatively alter our well-being.
Generally speaking, I think you can effectively use your body as a guide to tell you when sunglasses are truly necessary. If the light is uncomfortable to your eyes or causes you to squint, put on a hat, get in the shade or use sunglasses – temporarily. But I believe it's best to avoid wearing sunglasses automatically during virtually all daylight hours.