Cataracts are a clouding or 'misting over' of the lens of the eye. This affects normal vision, and cataracts will affect most people if they live long enough.
What Causes Cataract?
The most obvious symptom is a loss of clear or distinct vision, and occasionally poor vision in bright light such as car headlights or sunshine. Others include double vision, a reduction in the ability to distinguish colours, and an increase in the number of times reading glasses are being changed. Eyes with well developed cataracts in them have a characteristic 'milky' film over them, and one eye is usually affected before another.
Will I Have Any Tests Or Investigations?
A doctor will examine the eyes painlessly using an ophthalmoscope - a hand held eye instrument - and the cataracts can be clearly seen. There may also be colour vision tests or eye chart tests to try to assess the loss of vision.
What Treatment Might I Need For Cataract?
If a cataract only affects the very middle of the lens, eye drops are occasionally helpful. These dilate the eye, allowing more light to enter it and so reduce the symptoms. However, the vast majority of cataracts which require treatment will need surgery. There are three main methods used here;
• 1. In younger people, the usual cataract surgery method is to remove the particular lens fibres causing the cataract. This is a simple procedure, done under local anaesthetic, where the front capsule of the eye and lens are pierced and the fibres broken up. The body then usually absorbs any that are left behind.
• 2. An ultrasound technique called phakoemulsification. Here, the surgeon softens the lens with ultrasound sound waves and then removes it, leaving the back half of the lens capsule behind. This has the advantage that only small incisions into the eye are needed but may mean a second operation is needed later to produce a further improvement in vision.
• 3. Intracapsular surgery. In this type of treatment, the entire lens is removed. This has the advantage of rarely needing further surgery.
Cataract Surgery And Cataract Surgery Recovery
In all cases, once the cataract has been removed then the vision needs to be corrected - the lens only accounts for a third of the power of the eye - which can be done with strong strength glasses or contact lenses. Spectacles can only be prescribed if both eyes have been operated on, or if one is no longer used.
Intra-ocular implants (IOLs) are useful in patients who have had cataract surgery to one eye. Under anaesthetic, a plastic lens implant is placed in the eye after the cataract has been removed. This remains in place permanently, requires no maintenance, and is not felt by the patient or noticed by others. Spectacles for reading may still be needed but thick glasses are usually not required.
In general, once a cataract has been operated on and vision corrected the patient has satisfactory sight and is able to lead a normal life.
What Course Will The Illness Follow?
Most cataracts develop extremely slowly, and so a gradual loss of vision may not be noticed until the loss is severe. Cataract surgery is usually considered when the visual problems interfere with normal daily activities. If cataracts are severe and not treated there is a risk of long-term blindness. Many patients however require no treatment for their cataracts as they are able to lead a normal life with them.
Can I Do Anything To Help Myself?
There is some evidence that avoiding ultraviolet light can reduce cataract formation, so protecting the eyes from sunlight by wearing sunglasses when at altitude or on sunny days is sensible. Always report any change in your vision to your doctor and have an annual eye check with an optician.
Tell Your Doctor
1. How long have you noticed problems with your eyesight?
2. Do you have any blurred vision or sensitivity to light?
3. Have you always spent a lot of time in the sun?
4. Are there problems when you try reading close-up?
5. Is one eye worse than the other?
Ask your Doctor
1. Do I need to inform the driving license agency?
2. Will I need to stay in hospital for any length of time?
3. How quickly can I have surgery if I need it?
4. If I cannot have surgery, should I be registered partially sighted?
5. Can I have free eye checks?
By Dr Roger Henderson, MB BS Lond., LMSSA Lond.
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