Cataract

Cataract is a clouding of the lens of the eye. The lens is the transparent sphere within the eyeball, behind the pupil. The lens focuses light rays onto the retina to form a sharp image which is relayed to the brain by the optic nerve.

When cataract occurs, the lens loses its transparency. The cloudy lens prevents light rays from entering the eye, hence impairing the function of sight.

Cataract is not a tumour or a growth of tissue over the eye as is commonly feared. Cataract is due to physical changes in the contents of the lens. This disturbance results in the clouding of the lens.

Poor vision from cataracts affects 60% of all adults over the age of 60. However, cataracts can affect all ages as they also result from being inherited, injury, medications or diabetes.

• Cloudy, fuzzy, foggy or filmy vision
• Changes in the way you see colours
• Problems driving at night because headlights seem too bright
• Frequent changes in your eyeglass prescription
• Double vision
• Better near vision for a while (only in farsighted people)

These symptoms also can be signs of other eye problems.

Cataract surgery only clears the way for light to travel through the eye. Other eye diseases are not affected by cataract surgery.

Surgery is not necessary as long as vision remains satisfactory, but with time, vision may deteriorate. Surgery should be considered when poor vision interferes with daily activities.

Cataract surgery is most often performed under local anaesthesia on an outpatient basis. Most people do not need to stay overnight in a hospital. However, you will need a friend or family member to take you home.

Surgery is the only effective way to remove the cloudy lens. Cataract surgery is usually highly successful and more than 90% of the patients are able to regain excellent vision.

This has been made possible through technological advances in recent years and includes the use of small incisions, foldable lenses, the effective prevention of infection and early mobilisation. The operating microscope allows precision surgery with minimal trauma.

With the removal of the lens, an artificial lens is needed to substitute the function of focusing light rays onto the retina.

This may be done through the use of:

• Cataract glasses which are thick convex lenses
• Contact lenses
• Intra-ocular implants which are plastic discs implanted inside the eyeball by surgery. The eye is measured very accurately pre-operatively by ultrasound and the correct strength of intra-ocular lens is calculated

You can choose between general, local or topical anaesthesia. Discuss these options with your doctor.

You are allowed to read and watch TV right after surgery. You will use eye drops prescribed by your doctor. You will be seen for a check up on the first day after surgery. Your doctor will tell you when you are ready to be tested for your new glasses, and will refer you to an optometrist for this.

A cataract cannot return because the whole lens has been removed. However, in some people, the lens capsule can become cloudy. The cloudiness of the lens capsule, if it occurs, usually develops a year or more after surgery. It causes the same vision problems as a cataract does.

The treatment is a procedure called YAG capsulotomy. The doctor uses a laser beam to make a tiny hole in the capsule to let light pass. This is quick, safe and painless.

Serious complications are not common with modern cataract surgery. This type of surgery has a success rate of 95% in patients with otherwise healthy eyes, but no surgery is risk free. Although serious complications are not common, when they occur, they could result in loss of vision.

Examples of these are:

• High pressure in the eye
• Blood collection inside the eye
• Infection inside the eye (endophthalmitis)
• Drooping eyelid
• Retinal detachment
• Swelling or clouding of the cornea

Fortunately, these conditions are rare, but must be mentioned for completeness sake. Modern cataract surgery has become a safe, quick and predictable way of restoring the miracle of sight.