General Description
Cataract is a clouding of the eye's lens, which obstructs vision.
The most common symptoms are: cloudy or blurred vision; problems
with light, such as glare from lamps or the sun, or a halo or haze
around lights; colors that seem faded; double or multiple vision;
and frequent changes in eyeglass prescriptions. Cataract is the
most common vision disorder associated with aging, with half of
Americans ages 65 to 74 and 70% of those over 75 affected by the
disease.1 With increasing life expectancy, the number
of cases of blindness from this disorder may double by the year
2010.2 Cataract is the leading cause of blindness worldwide,
accounting for about 42% of all blindness, in spite of the availability
of effective surgical treatment.2 Cataract surgery is
the most commonly performed surgical procedure in the U.S., with
roughly 1.35 million cataract operations per year at an estimated
cost of $3.5 billion.2 During cataract surgery, the clouded
lens is removed and, in most cases, a clear, plastic replacement
lens (intraocular lens) is placed in the eye. In some cases, contact
lenses or cataract glasses are used instead of intraocular lenses.
Age-related cataract
The development of most cataracts is related to the aging process;
thus they are known as age-related cataracts. The most common
types of age-related cataracts are nuclear, cortical, and posterior
subcapsular cataracts, which are named for the area of the lens
where they are seated. Although these cataracts are most commonly
diagnosed in the elderly, they may be present during middle age,
but are usually too small to affect vision. It is after age 60
that most cataracts cause vision loss. Although most people will
develop age-related cataracts if they live long enough, some factors,
such as smoking3 and sun exposure,4,5 can
increase the odds of cataract development.
Other types of cataract
Although age-related cataract is the most common, there are many
types of cataracts that may affect different age groups. Congenital
cataracts are present at birth or develop in early childhood.
They often affect both eyes. Traumatic cataracts are cataracts
that develop as the result of injury to the eye. Secondary cataracts
are those that result from surgical complications or underlying
health conditions, such as diabetes. Like age-related cataracts,
these forms of the condition are treated with surgery.
Nutritional/lifestyle considerations
Although scientists are unsure what causes most cataracts, oxidative
damage to the lens appears to be a contributing factor. Numerous
studies indicate that antioxidants like vitamins A, C and E, lutein
and other carotenoids may have a protective effect against cataract
formation.6-15 The B vitamins riboflavin, thiamin,
and niacin also appear to have a protective effect,12-16
presumably due to their roles as components of antioxidant enzymes.
Antioxidant herbs such as bilberry and grapeseed extract may also
be helpful. Because smoking and sunlight exposure contribute to
the formation of free radicals and have been linked to an increased
risk for cataract development, quitting smoking and limiting sun
exposure (with sunglasses or broad-brimmed hats) are recommended.
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