A cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world. Nuclear cataracts usually are associated with aging. Cataract development is a normal part of the ageing process, so everyone develops a degree of cataract as they get older. However, it can also occur at a younger age, where it may be related to a previous injury to the eye, medication use (such as steroids), or chronic illnesses such as diabetes.
When should I have cataract surgery?
Symptoms of a cataract might include hazy or blurred vision, light sensitivity and glare, feeling of a "film" over the eye, difficulty driving or reading, general loss of contrast with yellowing of vision.
Cataracts are diagnosed during a routine eye examination, and early on, they do not require surgical intervention. Often just changing your glasses will satisfy your visual needs. A cataract itself is not harmful to your eye, so it is only worth having surgery when you feel the cataract is starting to affect your vision. However, when you feel that your vision is not good enough for normal activities and your lifestyle, you should consider cataract surgery. A decision to have a cataract operation will be made by you and us after making certain no other problems are contributing to your symptoms and visual change. People commonly ask us if their cataract is ‘ripe’ or ‘ready’. With modern surgical techniques, we can perform surgery at any stage when the cataract is affecting your daily life.
What does cataract surgery involve?
Cataract surgery involves removing your cloudy lens and replacing it with an artificial lens. It is normally performed as day surgery under local anaesthetic, so you are awake but your eye will not feel any pain. You will not be able to see properly during the operation, but you may notice bright lights or colours. You will need to lie relatively still during the operation; if you need to cough or adjust your position, please warn your surgeon.
We make small incisions (cuts) in the side of the eye and use ultrasound probes in a technique called ‘phacoemulsification’ (not lasers in standard operation, as is commonly believed) to remove your cataract, and then replace it with the artificial lens. This is made of plastic and stays in your eye forever, only rarely needing replacement. Measurements taken before the operation help us decide which lens strength is right for you. Usually, we aim to make you glasses-free for distance, so that you only need glasses for reading. However, there is a chance you will need glasses for both distance vision and reading after surgery, particularly if you have a history of astigmatism or an irregularly shaped eye. The operation usually takes approximately half an hour.
What are the risks?
Cataract surgery is usually very successful, with over 95 out of 100 of people noticing an improvement in their vision after surgery if there are no other pre-existing eye conditions. However, it is important to realise that there is always a risk of complications associated with any operation.
Some of the complications that may occur during the operation include:
Internal bleeding, Damage to other structures of the eye, including the capsule surrounding the lens, Incomplete removal of the cataract, Part of the cataract falling into the back of the eye.
Some of these complications can be dealt with at the time of the surgery or just after surgery. Potential complications occurring after the operation include:
Severe infection, Fluid accumulating in the retina, Detachment of the retina, Incorrect strength of lens inserted, Clouding of the membrane behind the lens
These complications can sometimes occur even if the operation itself is carried out perfectly. Many of these complications are manageable, although it may mean that other treatments may be required and that the recovery period may be longer than usual. This includes the need for additional surgery in approximately one in 100 cases. The most serious consequence of all the complications is the risk of loss of vision, which may be temporary or permanent. The chance of severe or complete permanent loss of vision in the operated eye is less than one in 1,000.
In approximately one in 10 cases, the membrane behind the artificial lens can become cloudy making your vision more blurred again. If this happens laser treatment may be needed some time after surgery. We would like to remind you that these risks are not common, with over 95 of every 100 operations occurring without any complications. If you have any pre-existing conditions (such as previous trauma or previous surgery) that may predispose your eye to be at a higher risk, you will be informed by your doctor.
Are there any alternatives?
The alternative to cataract surgery is to discuss with your optician if change in glasses can improve vision. You can delay surgery as long as you can function normally and you are getting eye check regularly. Occasionally, cataract can become dense after some time, which can increase the risk of the cataract surgery.