A cataract is a clouding of the lens inside the eye. The lens is just behind the pupil of your eye and is usually clear. Its job is to focus light onto the retina to form a clear image of what we see. When a cataract develops the image created on the retina appears out of focus and blurred.
Unfortunately you cannot really avoid cataracts as they are part of the natural aging process. Most people over the age of 65 will have some form of cataract and it usually occurs in both eyes, although one eye may be affected before the other. Cataracts may also develop earlier, for example if you are diabetic or are on steroid medication. A cataract may also develop if there has been trauma to the eye or if you have had eye surgery.
How does a cataract affect vision?
Often a cataract will feel like your glasses need changing - things will appear blurred and out of focus. 'Shadowing' or 'ghosting' can occur when looking at objects and you can also find you are more sensitive to light. Car headlights or even the sun can dazzle and cause glare. Cataracts can also cause colours to appear different such as appearing washed out or faded.
How are cataracts treated?
When a cataract first develops it can usually be treated simply by changing your glasses to improve your vision. Regular eye examinations are recommended to monitor the development of the cataract and your Optometrist will keep you advised. Cataracts generally tend to develop slowly and gradually and it will eventually reach a point where changing the glasses is no longer effective. Only when the cataract starts to interfere with day-to-day activities and you feel your vision is no longer adequate will an operation be advised to remove the cataract. The timing of this varies depending on individual symptoms and visual requirements and your Optometrist will be able to give you some advice when the time comes.
The operation involves removing the cloudy lens and replacing it with an artificial lens implant. This is carried out by an Ophthalmologist (a doctor specialising in eye care) at a hospital. It is quite a simple procedure and is usually carried out under a local anaesthetic. Small incisions are made in the eye and the damaged lens is removed. An artificial lens implant is then inserted in its place. Measurements will have been taken previously to determine the power of lens required for your eye so an additional benefit is that your new lens will correct most, if not all, of your distance vision. This means that you may not need glasses for distance vision after the surgery, however, you will usually still require reading glasses.
As only small incisions are used the eye does not usually require stitches and this helps to minimise the risk to the eye and speed up the recovery process. The operation usually takes about 30 minutes and most people go home from hospital a few hours later. You will be given some drops to use in the eye - usually an antibiotic drop to help prevent infection and a steroid drop to reduce swelling.
You will have to attend a follow up appointment with the Ophthalmologist a few weeks after the surgery to ensure that the eye is healing as expected. Once the eye has healed they will then advise an appointment with your Optometrist to sort out your new glasses. If you require cataract surgery in the second eye soon after the first one, they may recommend that you wait until both eyes have healed before seeing your Optometrist.
What are the risks?
Cataract surgery is usually very successful. Only a very small percentage of people experience any problems whatsoever. Even then, the most common problems are not serious and easily solved.
One of the most common complications is a thickening of the lens capsule. This is a membrane that holds the lens in place and when the cloudy lens is removed, the artificial lens implant is positioned into it. If this capsule does thicken it also goes cloudy and can give you similar symptoms to the original cataract. It is not the same as a cataract however, and does not require another cataract operation. It can be successfully treated with a small laser. The risk of this is even lower than the risk of the cataract surgery itself and once treated it does not recur.
Other complications are much rarer but include infection in the eye, retinal detachment and cystoid macular oedema. Cystoid macular oedema is the accumulation of fluid in the macula. As already stated, this is the part of the retina responsible for your detailed vision, so if fluid occurs here it does affect your vision. This usually improves in 2-3 months although it may require treatment to help progress.