The eye is an astonishing organ of the body, working
constantly to turn light into streams of nerve impulses which the
brain can convert into visual images.
Although our vision dominates how we understand the world around
us, most people take it for granted until they realise they have a
problem. From midlife onwards several different eye conditions
become common and by the age of 45 most people have noticed that
they can’t see as well as they once could. Some of these
problems can be corrected with glasses or contact lenses while
others need medical treatment or surgery. However, there is plenty
that you can do yourself to keep your eyes healthy and delay the
changes associated with aging.
A diet rich in antioxidants will help to combat the ravages of
time and environmental pollutants. This means plenty of vitamins A,
C and E and carotenoids (good sources include red, orange and
yellow vegetables and fruit). Selenium, found in liver, kidneys and
sea food, is also important (UK soil levels of selenium are low so
vegetables are rarely a good source). Flavonoids, found in fruit,
vegetables, pulses, wine and tea (especially green tea), also have
powerful antioxidant effects.
Have eye tests regularly
Many diseases can be detected only by a thorough examination of
the inside of the eye, especially during their early stages. Deal
promptly with any sudden problems or trauma. Wear sunglasses to
protect your eyes from high doses of ultraviolet light in bright
sunshine that can speed up age-related changes in vision and avoid
eye strain by limiting the amount of time you spend in front of a
computer screen.
Time for reading glasses?
As you age you may find it difficult to focus on objects close
to you. This problem, presbyopia, usually starts at about 40-45 and
is so common that it is regarded as a normal change of aging. The
lens inside the eye becomes larger and stiffer and less easily
changes its shape to focus light coming from close objects. Glasses
or contact lenses for short or long sightedness don’t help
presbyopia and can even make it worse. Neither can surgery help.
The only answer is to wear special reading glasses, or change to
bifocal lenses.
Age-related macular degeneration
AMD affects around 1 in 10 people over 40 and is the most common
cause of blindness in the developed world. In this painless
condition, the macula or central part of the retina (the
light-receiving membrane at the back of the eye), becomes damaged
due to the irreversible death of light-receptor cells or the
invasion of leaky, unwanted blood vessels into the retina,
resulting in blurred central vision.
Once the condition has reached an advanced stage, there is
little effective treatment although new drugs have recently been
introduced in one less common form of AMD known as wet AMD.
Research has shown that people whose diet is rich in green leafy
vegetables have a lower risk of developing AMD. In the USA the
National Eye Institute’s Age-Related Eye Disease Study found
that a high-dose formulation of antioxidants and zinc significantly
reduced the risk of advanced AMD, although it could not cure the
disease or restore lost vision. This formulation included 500mg of
vitamin C, 400iu vitamin E, 15mg beta-carotene (equivalent to
25,000iu vitamin A) and 80mg zinc. These high levels of nutrients
are difficult to achieve from diet alone so researchers now
recommend that anyone at risk of advanced AMD should consider
taking supplements.
More recently, studies have shown that two particular
antioxidant carotenoids called zeaxanthin and lutein occur in high
concentrations in the macula, helping to keep it healthy. Some
people who are at increased risk of AMD (e.g. smokers) have low
levels of zeaxanthin and lutein in the macula, while people with
high levels in their diet appear to experience less damage to the
eye and a reduced risk for advanced AMD. Spinach and greens are a
good source of zeaxanthin and lutein, but supplements may be a more
reliable way to ensure you get enough.
Cataracts, glaucoma and diabetes
Micronutrients may also be important in reducing the risk of
cataracts - a clouding of the lens. Cataracts is a common condition
after the age of 60 and by 75, 70% have visually significant
cataracts. Once formed, they must be surgically removed. Factors
that may contribute to cataract development are low calcium levels
in the blood, diabetes, excessive exposure to ultraviolet light and
smoking. The nucleus of the lens is particularly sensitive to
nutrient deficiencies. Research has shown that vitamin A and B
types such as niacin, thiamin and riboflavin may protect against
cataracts, while other studies have linked high zeaxanthin and
lutein consumption with a lower risk.
About one in 90 people suffers from glaucoma, a condition where
the pressure inside the eye rises, damaging the optic nerve. This
causes visual loss which can develop very gradually and go
unnoticed until permanent damage has been done.
It’s very important to be tested regularly for glaucoma,
particularly when others in your family have had the condition.
Medication or surgery can reduce the pressure. In some cases of
glaucoma, magnesium has been shown to help improve vision by
improving blood flow. However, this early research may be relevant
only to a small proportion of people and is no substitute for
proper medical treatment. Diabetics are particularly vulnerable to
glaucoma, cataracts and many other eye problems, which may develop
even before the diabetes has been diagnosed.
Laser therapy has already meant that hundreds of thousands of
people have been able to throw away their glasses, although it is
expensive and still carries a significant rate of complications. In
the future new technology and treatments such as gene therapy may
lead to much greater improvements, and even a cure, of many common
eye problems. But for now at least we all need to do everything we
can to look after our eyes.
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