#Sunlight may put you in the dark: Protect your #eyes from #UVrays

Sunshine, sandy beaches, swimming, picnics, outdoor sports – it’s time to enjoy the season.  We want to be carefree but we need to be careful – especially with our eyes. We all use sunscreen to protect our skin, but our eyes need protection too.

We know sunlight can be beneficial, causing production of vitamin D3 in the skin.  Natural light also helps us see better and sleep better -- but too much can be destructive. We still don’t know exactly how much is safe for our eyes. We have to protect three parts of the eye: the cornea, the lens and the retina.

How does the sun hurt our eyes? 

Sunlight contains ultraviolet (UV) radiation. There are two types of UV radiation:

UVA - can pass through the cornea (outer layer of the eye) and reach the lens making it cloudy and causing cataracts. It can also harm the retina inside the eye causing macular degeneration leading to blindness.

When the sun is overhead and you stare at it -- in 90 seconds it will cause a burn to the retina. A few hours later it takes several minutes to burn you and it is almost impossible at sunset.  While most of us will not stare at the sun we should limit or avoid exposure.  From 10 AM to 2 PM is the worst time for sun exposure – for your eyes or skin.

UVB - this type of UV radiation is unlikely to cause cataracts and macular degeneration. UVB rays may cause pingueculae and pterygium. These are growths on the eye's surface which can become unsightly and cause cornea problems as well as distorted vision.

pingueculae

In high, short-term doses, UVB rays also can cause photokeratitis, a painful inflammation of the cornea which is la "sunburn of the eye." It can make the eyes red, light sensitive and cause a gritty feeling and excessive tearing. Fortunately, these symptoms are usually temporary and rarely cause permanent damage to the eyes.

"Snow blindness" is the common term for severe photokeratitis, which causes temporary vision loss usually lasting 24-48 hours. So UV eye protection is not just for the summer.

New research suggests the sun's high-energy visible (HEV) radiation (also called "blue light") may increase your long-term risk of macular degeneration. This radiation penetrates deeply into the eye to the retina.  People with low levels of vitamin C and other antioxidants in their blood have a higher risk of retinal damage from HEV radiation. According to a study published in the medical journal Archives of Ophthalmology, HEV radiation — especially with low antioxidants — is associated with the development of macular degeneration.

Who needs protection from harmful UV light?

Everyone needs this protection, especially those who work or play in the sun: construction workers, farmers, drivers of taxis and trucks, sports participants and spectators, police officers, skiers, lifeguards, and beach goers. All people who work outdoors can get eye damage from the sun.

Contact lens wearers are at risk of eye damage. Soft contact lenses can transmit up to 50 percent more UV light to the eye. So even if your contact lenses provide UV protection, you still need sunglasses.

Vacations at the beach, with highly reflected water and sand all around, is a place of high exposure to UV and HEV light.  The radiation is reflected into your eyes. And fresh snow is an even greater risk, reflecting up to 88 percent of the light that hits it into your eyes.

Geography is a factor--the closer you live to the equator, where the UV and HEV radiation is stronger--the greater the UV exposure. Altitude is a factor as well--UV radiation intensity increases about 5 percent for every 1,000 feet of elevation.

Surprisingly, cloud cover doesn't decrease UV levels much. Your risk of UV exposure can be quite high even on hazy or overcast days. This is because UV is invisible radiation, not visible light, and can penetrate clouds.

Anyone else to protect? - People taking medications may be at risk. There are many drugs that make your eyes more sensitive to sunlight (photosensitive), including certain tranquilizers, diuretics, oral contraceptives, antibiotics (like tetracycline), anti-diabetic and anti-hypertensive medications, and even artificial sweeteners such as cyclamates. You can ask your pharmacist about a medication or look up the drug side effects online.

Babies and young children

Children may be outside for long periods of time in the sun. I see infants and toddlers pushed around in their strollers with no hat, no sunglasses and many times no skin sunburn protection – it makes me ill. With their clearer corneas and lenses, children's eyes actually admit greater levels of UV and HEV light than adults. So the UV radiation can go straight to their retinas. Even small amounts, accumulated over time can lead to damage – and you won’t know it until years later. Up to half of a person's lifetime exposure to UV radiation can occur by age 18. The damage might not show up for 30 years.

Don’t forget grandpa and grandma

The effects of UV radiation keep adding up as a person gets older and receives more and more UV and HEV radiation. As we live longer and longer, the average person is more likely to be affected by eye diseases caused by years of exposure to this radiation. So if grandpa is 70 and will live to 95, there is still time to protect his eyes so he is not blind later on.

Computer screens and other light source effects on your eyes

Working under bright fluorescent lights in an office or a store -- or spending hours in front of a computer screen can also damage the eyes. Laboratory workers who are exposed to UV light as part of their job are also at risk. All of these people need eye protection.  UV protection can be put in eyeglass lens that can be used indoors or protective screens can be used on monitors.

Digital screens give off little or no UVA or UVB radiation and will usually not cause eye damage such as cataracts. However, digital screens do expose your eyes to HEV (blue light). The HEV exposure you get from screens is small compared to the amount of exposure from the sun. But the long-term effects of screen exposure and how close we are to screens is cause for concern. Research shows that children’s eyes absorb more blue light than adults from digital device screens. There are many other sources of HEV: CFL (compact fluorescent light) bulbs, LED light, flat screen LED televisions, smart phones, and tablet screens. 

Protection against sun exposure

The longer the eyes are exposed to sun radiation, the greater the risk of developing cataracts or macular degeneration later in life. It is not clear how much exposure to solar radiation will cause damage. So whenever you spend time outdoors, wear quality sunglasses that offer full UV protection. A hat or cap with a wide brim can cut out a lot of UV.

Misleading claims about sunglass UV protection can be confusing. A pair of glasses might be labeled UV absorbent, but the label might not say exactly how much UVA and UVB rays are blocked. Sunglasses should be labeled UV 400 to ensure complete blockage of UV. This is not the time to look for bargains – your eyes are too important! The skin around your eyes and your eyelids is susceptible to skin cancer – we don’t usually put suntan lotion there.  To protect as much of the delicate skin around your eyes as possible, try sunglasses with large lenses or a close-fitting wrap around style.

Some sunglasses come with amber, green or gray lenses. The colors do not block UV but can increase contrast, which may be useful for athletes who play sports such as baseball or golf. Polarization reduces glare coming off reflective surfaces like water or pavement. It doesn’t protect from sun radiation, but can make activities like driving or being on the water safer or more enjoyable. A darker lens that doesn’t have the right UV protection will allow the pupil of the eye to dilate (widen), letting in damaging radiation.

Nutrients that protect your eyes

You can protect your eyes from the inside out with key nutrients:

Vitamin C: lowers risk of cataracts and macular degeneration. Find it in citrus fruit like grapefruit and orange juice, as well as strawberries, kiwi and green peppers. Most foods with vitamin C also contain bioflavonoids which protect the blood vessels in the eye.

Lutein & Zeaxanthin: These antioxidants aid in prevention of age-related macular degeneration and cataracts. Food sources are orange and yellow colored vegetables like carrots and sweet potatoes; dark green, leafy vegetables (especially spinach and kale); and eggs.

Zinc: This mineral helps release Vitamin A from the liver, which in turn helps your body make melanin, a protective pigment in the eyes. Melanin is the same pigment that protects your skin from the sun. Zinc is found in high concentration in the eye -- in the retina. Red meats, poultry, and eggs supply larger doses of zinc but plant sources are available in wheat germ, nuts, black-eyed peas, and tofu. Vegetarians need several plant-based choices each day because there is lower absorption of zinc from these foods as compared to the non-vegetarian options.

Vitamin E: This super antioxidant protects the eyes from the damaging effects of the sun on the fragile cells in the eyes (and rest of the body). Nuts or nut butters have some vitamin E, as do wheat germ and cooking oils such as soybean, sunflower and canola.  Given the limited types of foods or the calorie content, some people prefer to take a vitamin E supplement. 

Essential fatty acids: Omega 3 fatty acids, specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are both important for vision development and retinal function. DHA is found in high concentrations in the retina. These important good fats are found in higher-fat fish, such as salmon and mackerel; fortified foods such as eggs and various types of milk; green, leafy vegetables; and nuts and seeds, like flaxseed and walnuts.

Bilberry, blueberry and black currants: These antioxidants contain anthocyanins that are important for eye health because they stay in the thick watery fluid filling the space between the lens and the cornea. Blueberries also contain anthocyanins. The vitamin E in blueberries may help stop the formation of cataracts, or clouding of the eye lens.

Your eyes are precious so take care of them. They are vulnerable to damage by UV radiation and nutrient deficiencies. There are many types of radiation exposure and they all add up. Please write to me with any questions you may have.

 

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