Cataract is clouding of the lens inside the eye, with the lens becoming gradually more opaque over time. This process is usually quite slow, occurring over several years, although occasionally it can develop more quickly over a matter of months. Cataract is a very common eye condition and is the commonest cause of poor vision worldwide. It can affect people of any age, although it tends to be more common as you get older.
How does cataract affect vision?
Cataract in itself is rarely harmful to the eye, and almost always affects only the vision. It does not cause pain or redness of the eye. In the earliest stages, people may experience glare at night from streetlights and car headlights, which can affect driving at night. People often find that when reading newspapers or books with fine print, the words jumble or that they get tired of reading and have to put the paper or book down. There may be difficulty adjusting between different lighting conditions, for example, when going indoors after being outside in a sunny environment or vice versa. Eventually, as the cataract progresses, the overall vision becomes misty in the affected eye, and if the cataract is not treated the vision can become significantly reduced.
The only effective treatment for a cataract is surgery which is safe and highly successful. Modern cataract surgery is performed under local anaesthesia and often only anaesthetic eye-drops are required. The procedure is done as a day-case and usually takes about 15 to 20 minutes.
Before the operation, various eye measurements are taken in the eye clinic which allows selection of the most suitable lens implant. The surgery involves making small cuts in the wall of the eye and breaking up the cataract into small pieces using an ultrasound probe (phakoemulsification).
Once all the small cataract fragments have been removed from the eye, an intraocular lens implant is introduced where the cataract had been. In most cases a lens implant is chosen which provides excellent distance vision, usually without the need for spectacles.
The recovery period is short and the vision in the operated eye is much improved within a few days of surgery. The eye may feel slightly sore for a day or two. Often it quickly becomes apparent that the other eye is also quite blurred due to cataract, and cataract surgery can be arranged for the second eye.