The Eyes Have It
The Eyes Have It
Eyes going bad? Blurry vision, whether you are five or 50, usually signals a change in your refractive error, which is just a fancy way of saying the ability to focus your eyes. Some of these errors include myopia (short-sightedness), hyperopia (long-sightedness), presbyopia (unable to focus on near objects) and astigmatism (visual distortion). We can generally thank our genes for these problems – all of which can be easily corrected with glasses, contact lenses or laser surgery.
But there is another condition, known as low vision, which is a loss of vision that is so severe it cannot be corrected with glasses, contact lenses, medication or eye surgery. Most people develop the problem with age-related eye diseases. These include cataract (clouding of the lens causing hazy, blurry vision); glaucoma (optic nerve damage causing loss of peripheral vision, which makes driving tricky) and macular degeneration (retinal damage which affects central vision, making reading difficult). Heredity and eye injuries can also lead to low vision. It makes everyday tasks more difficult, takes the enjoyment out of life and can lead to a loss of independence.
FINDING YOUR WAY
The message is that as we age, our general health affects the way we see, so to have healthy eyes and good vision, you need a healthy body. And it’s a message we keep seeing in major studies on eye health.
A large-scale US study at the University of Madison-Wisconsin found those who had genetic risk factors, smoked and were in the highest-risk diet and exercise categories were more than four times more likely to have age-related macular degeneration (AMD), compared with women who did not have genetic risk factors, ate a healthy diet (see the list of foods on the opposite page) and got at least 10 hours a week of light exercise (such as housework or walking at a pace at which you can sing) or at least eight hours of moderate activity (such as brisk walking).
The connection between supplementation and eye health has been the focus of two benchmark studies in the US – the Age-Related Eye Disease Study 1 and 2 (AREDS1 and 2). In 2001, researchers found taking daily high doses of vitamins C and E, beta-carotene, zinc and copper can help slow the progress of AMD. The second stage of the study in 2011 showed other nutrients also help protect eye health (namely lutein and zeaxanthin), while taking beta-carotene out of the formula and reducing zinc. Other studies from the Medical Harvard School show the addition of omega-3 fatty acids to the diet is beneficial (see Super Supplements, right, for more information on how these nutrients can help).
The AREDS authors believe people with advanced AMD can slow its progression by taking a combination of antioxidant and zinc supplements (always talk to your doctor about the best approach for your needs). These are the supplements highlighted in their studies.
Lutein and Xeanthin
Our bodies do not make either of these carotenoids, the pigments that give certain foods, such as carrots, their colour. Carotenoids are found in the macula and retina of the eye and may help prevent them from damage.
Omega-3 Fatty Acids
Two omega-3 fatty acids – docosahexaenoic acid (DHA) and obstinateness acid (EPA) – are important for proper visual development and retinal function. These fatty acids help reduce the risk of diabetic retinopathy, which can lead to blindness if untreated.
Essential for growth and development, vitamin A plays an important role in the health of the retina, our ability to see the full spectrum of light and to adapt to low light and darkness. It also nourishes other parts of the eye, including the cornea, the clear covering on the front of the eye. Without enough of this vitamin, our eyes can’t produce the moisture needed to keep the cornea properly lubricated.
The AREDS findings on this vitamin is supported by a decade-long study from King’s College London, published in the journal Ophthalmology in March last year. It found participants with a higher intake of vitamin C were associated with a 33 per cent risk reduction in cataract progression and had “clearer” lenses after 10 years, compared with those who had consumed less vitamin C.
Our body does not create vitamin E, it needs it. This is why daily intake of this nutrient is important. It not only plays a main role in the immune system, stopping cell damage from free radicals, it reduces the progression of AMD and cataracts, too.
Zinc helps vitamin A create a pigment called melanin, which protects your eye. As the AERDS2 study shows, it works together with the other antioxidants to help protect your eyes. Too much zinc can be toxic though, so stick with the recommended dosage.
Eat a handful of these little gems for a decent dose of vitamin E, as well as iron, manganese, selenium, vitamin B6, zinc, protein and fibre, and essential linoleic acid … talk about good things in small packages!
These are mighty when it comes to zinc, so you only need a couple to get your RDI of 8-12mg. Not an oyster fan? Try beef or lamb, or wheatgerm.
All fish and shellfish contain omega-3 fatty acids but higher concentrations are found in oily varieties such as salmon, mackerel, anchovies, trout, herring and sardines. Aim to eat fish or seafood two to three times a week – either fresh, frozen or the tinned variety.
One of those great versatile foods you can have for breakfast, lunch or dinner, eggs contain both lutein and xeanthin. And don’t worry about your cholesterol levels – it’s not the cholesterol in foods that drive up our blood cholesterol levels, it’s actually the amount of saturated trans fats we eat. Most of the fat in eggs is the “good” unsaturated type our bodies need to be healthy.
This is just one of many citrus fruits that can help keep your vitamin C levels topped up. You can also add kiwifruit to your fruit bowl, red capsicum to your stir-fries and tomatoes to your salads to super-charge your diet with this essential nutrient.
It is packed with all sorts of goodies such as fibre and potassium, as well as vitamin A, so to get more than double your recommended daily intake of this vitamin, throw a sweet potato into the oven with the skin on and bake it for about 45 minutes. Or next time you’re making a mash, use sweet potato instead of the regular white tater
DIABETES AND YOUR EYES
We know that a well-balanced diet helps you stay at a healthy weight, which lowers your odds of age-related diseases such as type-2 diabetes – a major cause of preventable blindness, according to the World Health Organisation.
The general risks of the disease are often talked about, but one aspect we don’t hear so much about is how it affects your eyes later in life. Diabetes affects eye health when changing levels of blood sugar (glucose) cause vision to become temporarily blurry. This can lead to premature cataracts. Another condition is retinopathy, which causes damage to the tiny blood vessels in the retina.
Macular Degeneration: do the test
According to Macular Degeneration New Zealand (MDNZ), one in seven people over 50 will get macular degeneration. So, if you are 50 or over, it’s a good idea to get your eyes tested and macula checked. Take the online test at mdnz.org.nz, or for more information about the disease, call the MDNZ Support Line on 0800 622 852.