Cataract | 5 min read

A cataract is a frosting or clouding of the lens inside the eye. The most common cause is ageing but may be accelerated by diabetes or eye trauma. At the age of 65, almost half the population has developed an early cataract. By the age of 70, almost everyone has developed a cataract.

Cataracts can take anything from a few months to many years to develop. Sometimes the process stops in the early stages and vision is not seriously affected. In other cases, the cataract continues to develop and interferes with vision. Cataracts usually develop in both eyes, but they may develop at different rates, so vision in one eye is often significantly better than in the other.

Signs and Symptoms

The key symptom is blurred vision that worsens over a period of months or years. Some people notice that things seem dim with one eye and brighter with the other, while printed images may have a ghosted outline. Colours become less distinct and many patients are sensitive to light and glare (e.g. the sun or oncoming headlights). Other signs and symptoms of cataracts may include:

  • Poor night vision
  • Need for brighter light for reading and other activities
  • Frequent changes in eyeglass prescription

Even if other factors, such as glaucoma or age-related macular degeneration, are contributing to sight problems, the removal of the cataract and replacement of the lens should ensure improved vision.


The key to living with cataracts is knowing when it’s time not to live with them anymore. Usually, this happens when your normal lifestyle — reading the morning paper, driving to the local shopping center or seeing the expression on the face of a child or grandchild — is jeopardised by impaired vision.

Cataracts are usually diagnosed during a standard eye examination by a qualified optometrist. If you think that your eyes are affected, go to your optometrist to check. The optometrist can also look for other common eye conditions, such as age-related macular degeneration or diseases that affect the optic nerve (glaucoma).

If you have cataracts, the optometrist will monitor them and advise if and when you might need treatment — people often live with them for many years without needing an operation. There is no set level of dimming of vision before an operation is recommended but if the condition begins to affect your lifestyle or you can no longer meet the legal sight requirements for driving, you should seek help.


Advanced surgical methods make cataract surgery one of the most successful surgical procedures performed today. More than 95 percent of the people who have a cataract removal end up with better vision.

Using microsurgery and local anaesthesia, an eye specialist (ophthalmologist) removes the cataract, leaving much of your eye’s natural lens capsule in place. The capsule helps support the clear artificial lens that the surgeon inserts to replace the cloudy lens. The procedure is usually done on an outpatient basis and takes less than 1 hour. If both eyes are affected, surgery is usually performed on one eye at a time, allowing the first eye to heal before surgery is done on the second one.

Frequently asked questions

Can cataracts spread from eye to eye? No. But often they develop in both eyes at the same time.

Has my cataract been caused by overuse of my eyes? No. Cataract is not caused by overuse of the eyes and using the eyes when the cataract start will not make it get worse.

Are there different kinds and causes of cataract? Yes, certain diseases may predispose you to getting a cataract. Diseases like diabetes speeds up the development of cataracts. Certain medications, like steroids, may also speed up the development of cataracts. Injuries to the eye may also cause a cataract. Babies rarely may be born with a cataract.

Are cataracts just a part of getting old? Almost everyone will develop a cataract, if you live long enough. Certain people develop cataracts earlier than others.

I seemed to have to go to the optician more to get new glasses. As cataracts progress, you may experience more frequent prescription changes. Eventually glasses will no longer improve your vision.

When do I need my cataract treated? If your cataracts are interfering with your daily activities, then you should have your cataract removed

What kind of visual result can I expect after the cataract removal? After having your cataract removed, vision will improve, colours will appear brighter, and the misty vision will be removed. 98% of people undergoing cataract surgery have a favourable outcome. Cataract surgery is one of the most successful surgical procedures.

Could anything have been done to stop me developing cataracts? There is no known prevention for cataracts. Modern cataract operations are highly successful for the majority of patients.

Are cataracts removed by laser? No. Surgery is the only effective way to remove a cloudy lens. Laser may be used to assist the surgeon.

I have cataract developing in both eyes – are both treated at the same time? Usually not. Generally, the worst eye is treated first.

Do I need any special tests before the cataract surgery? Yes. The doctor will carry out special tests to measure your eye. This helps decide the strength of the intraocular lens which replaces your natural lens. New instruments to measure the size of lens you require, are highly accurate.

What does the cataract operation involve? The procedure is painless. Cataract surgery is usually performed under sedation by a eye specialist or eye surgeon. Local anaesthetic is applied, and the operation is performed. Cataracts are removed using a process called phacoemulsification. This technique uses sound waves to soften the lens, which is then removed through a tiny tube. A new lens is then placed into the eye. The entry points into the eye are so small, that they do not require stitches.

What kind of anaesthetic is necessary? Most operations for cataract surgery are done using local anaesthetic. An anaesthetist will give you sedation. Alternatively, you may decide that you prefer general anaesthetic.

Dr Akiel Asvat, Ophthalmologist, Icare, Sandton.

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