A cataract is a loss of transparency, or clouding, of the normally clear lens of the eye. This lens is a part of the eye that helps focus light on the retina. It is located behind the iris.
What causes it?
Your eye works much like a camera. Light rays focus through your lens on the retina, a layer of light sensitive cells at the back of the eye. Similar to film, the retina allows the image to be “seen” by the brain. But over time, as one ages, chemical changes occur in the lens that make it cloudy and prevents light rays from passing clearly through it; this cloudy lens is called a cataract.
Thus ageing is the most common cause of cataract. Other causes include trauma, medications such as steroids, systemic diseases such as diabetes and prolonged exposure to ultraviolet light. Occasionally babies are born with a cataract (known as “congenital cataract”).
What are cataract symptoms?
The typical symptom of cataract formation is a slow, progressive and painless decrease in vision of variable degrees. The loss of transparency of the lens may be so mild that vision is
hardly affected, or so severe that no shapes or movements are seen, only light and dark.
Other symptoms include:-
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Blurring of vision |
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Poor night vision |
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Glare, particularly at night |
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Frequent eyeglass prescription change |
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A decrease in colour intensity |
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A yellowing of images |
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Double vision (in rare cases) |
Ironically, as the lens gets harder, people who are farsighted (or hyperopic) experience improved distance vision and are less dependent on glasses; this however is a temporary state.
People who are nearsighted (or myopic) become more nearsighted, causing distance vision to be worse. Some types of cataracts affect distance vision more than reading vision;
likewise, the opposite can happen affecting reading vision more than distance vision.
What can I do to avoid cataracts?
Reducing the amount of ultraviolet light exposure by wearing sunglasses may reduce your risk of developing a cataract, but once developed there is no cure but to have the cataract surgically removed. Glasses or contact lenses cannot sharpen your vision if a significant cataract is present
Who can be treated?
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People with visually significant lens cloudiness |
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People of any age |
A comprehensive eye examination including visual acuity test, tonometry (measurement of the pressure inside the eye), pupil dilation, cornea measurements and tests to measure the size of the eye will determine your suitability for the procedure.
How is cataract treated?
The time to have the surgical procedure is when your vision is bad enough that it interferes with your lifestyle (eg you are unable to read, work or drive). Cataract Surgery is a day-surgery operation. The cloudy lens is removed through a tiny incision and a foldable focusing implant is put in its place.
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