Cataracts

What are Cataracts?

Cataracts are a very common eye condition. As we get older the lens inside our eye gradually changes and becomes less transparent (clear). A lens that has turned misty, or cloudy, is said to have a cataract. Over time a cataract can get worse, gradually making your vision mistier. A straightforward operation can usually remove the misty lens and replace it with an artificial lens to enable you to see more clearly again.

This information is about cataracts in adults. Some children develop cataracts, called congenital cataracts, before or just after birth. They can also be related to a number of infective and inflammatory conditions, but these are usually dealt with in a different way to cataracts in adults.

When you look at an image or object, light passes through the front of your eye, and is focused by the cornea and then the lens onto the retina. The lens is normally clear so that light can pass directly through to focus on your retina (the lens is clear because of the way the cells in the lens are arranged). The lens focuses light onto the retina, which converts the light into electrical signals. A network of nerves delivers these signals from the different parts of the retina to the optic nerve and then onto the brain. The brain interprets these signals to “see” the world around us.

The lens can change shape, allowing us to focus on objects at different distances, called “accommodation of vision”. As we get older, the lens isn’t able to change shape as well as it used to; even people who can see clearly in the distance without glasses will need reading glasses to see things up close. This process is not caused by a cataract.

Cataracts result from changes in the way the cells of the lens are arranged and their water content, which causes the lens to become cloudy instead of clear. When this happens, light cannot pass directly through the lens and you may notice problems with your vision. A cataract is not a growth or a film growing over the eye, it is simply the lens becoming misty.

What causes Cataracts

Cataracts can be caused by a number of things, but by far the most common reason is growing older. Most people over the age of 65 have some changes in their lens and most of us will develop a cataract in time. Apart from getting older, the other common causes of cataract include:

  • diabetes
  • trauma
  • medications, such as steroids
  • eye surgery for other eye conditions
  • miscellaneous eye conditions.

In general, the reason why you have developed a cataract will not affect the way it is removed. Most cataracts are caused by natural changes in the lens, which happen as you get older. However, the following factors may be involved in cataract development (please note that these are only suggested causes which are the subject of ongoing research):

  • tobacco smoking
  • lifelong exposure to sunlight
  • having a poor diet lacking antioxidant vitamins.

What are the symptoms and diagnosis of Cataracts

Cataracts usually develop slowly and although symptoms vary, there are some symptoms that most people experience. Most people will eventually develop a cataract in both eyes, though one eye may be affected before the other. When your cataract starts to develop, you may feel your sight isn’t quite right. For example, if you wear glasses you may feel that your lenses are dirty, even when they’re clean. Gradually, you may find your sight becomes cloudier and more washed out. Edges of stairs or steps become more difficult to see and you may feel you need a lot more light to read smaller print.

Another common symptom of a cataract is a problem with bright lights. Lights can seem to glare, or you may find that the headlights of a car dazzle you more than they used to. You may also notice a slight change in your colour vision – things may appear more yellow than before. This often happens if one eye develops a cataract first and colours look different when you compare one eye with the other.

If you notice any of these changes, you should have your eyes tested by an optometrist (optician) who will be able to tell whether you have a cataract or not. The optometrist will then discuss the degree to which the cataract is affecting your vision and if you agree, refer you via your GP to an eye clinic. You may be told during the eye test that you have early cataract or initial signs of a cataract which does not need referral. If you are unsure about anything during the eye test then ask to have it explained.

If a cataract isn’t removed, your sight will become increasingly cloudy. Eventually, it will be like trying to see through a frosted window or a heavy net curtain or fog. Even if your cataract gets to this stage, it can still be removed and your sight will be almost as it was before the cataract developed.

How is a Cataract treated?

The only effective treatment for cataracts is surgery to remove your cloudy lens and replace it with an artificial lens implant. This is done by an ophthalmologist in hospital. Lasers aren’t used to remove cataracts and there is no evidence to suggest that changing your diet, taking vitamins or using eye drops can cure cataracts.

The operation to remove your cataracts can be performed at any stage of their development. There is no longer a reason to wait until your cataract is “ripe” before removing it. However, because any surgery involves some risk, it is usually worth waiting until there is some change in your vision before removing the cataract. This is something to discuss with your optometrist as a good time to refer may vary from person to person.

Most people choose to have their cataracts removed when the change in their vision starts to cause them difficulties in everyday life. The timing of this varies from person to person. If you have problems in bright light, or you find reading or getting out and about, cooking or looking after yourself increasingly difficult then it may be time to consider having the cataract removed. When you attend your appointment in the eye clinic you need to make clear to the specialists any everyday problems you are having.

Many people with cataracts are still legally able to drive. If you have any concerns about whether you should be driving, your optometrist should be able to tell you whether your sight is within the legal limits for driving. Sometimes people may be legally able to drive but might find driving difficult in bright sunlight or at night. If this is the case, then you may think it is a good time to consider having your cataracts removed.

Pre-surgery

Before you have your cataract surgery, your eye health and general health will be checked carefully in what is often called a pre-operative assessment. Your vision and your eye will be assessed very carefully. This is usually done by a machine which measures the length of your eye ball and the shape of the front of your eye. These tests help the ophthalmologist decide which lens to implant when they perform your operation, to make sure your vision is as good as possible after the surgery. If you have a cataract in both eyes the ophthalmologist will use these tests to decide which cataract to remove in the first operation. In most cases, this is the eye with the worst cataract.

Surgery

Cataract surgery usually takes about 30 to 40 minutes and most people go home from hospital a few hours later. It is usually done with a local anaesthetic, which means you will be awake during the operation but you won’t feel any pain. You can talk to the operating team if you need any assurance. The local anaesthetic may involve drops and an injection or just drops.

For your surgery, you will be given drops to dilate your pupil. Your face will be covered by a sheet, which helps to keep the area around your eye clean during the operation. To remove the cataract, the ophthalmologist needs to remove the natural lens in your eye and replace it with a plastic lens implant. The most common way to remove cataracts is called phacoemulsification. This technique uses high frequency sound energy to break up your natural lens with the cataract. Only really small cuts are used, so you don’t need any stitches, and this helps to speed up your recovery from the surgery. Usually, the ophthalmologist uses a machine which acts as a microscope to get the best view of your eye as possible.

The lens in your eye is made up of different layers and the outside layer is called the lens capsule. During the operation, the ophthalmologist makes a circular tear in anterior part of the lens capsule so they can reach the lens inside. Using another instrument, the ophthalmologist can break up your lens and the cataract inside your eye, and remove it using ultrasound and suction. Your lens capsule is kept in place so that the artificial lens implant can be placed inside it. The tiny implant is folded so that it can be put into the eye through the same incicision that was created to remove the cataract. Once it reaches the right position, the ophthalmologist unfolds the artificial lens so that it sits in the right place inside the capsular bag.

As you are awake during the operation, you will be able to hear what is happening in the operating room. You can also communicate with the ophthalmologist and the nurses who are on hand to reassure you. Because the eye is anaesthetised and your pupil is dilated, you may be able to see some lights and movement but not the details of the instruments used. You should not feel any pain in your eye.

A day after your operation, your eye will be examined in Dr Joseph’s refractive suite. Your eye will be covered with a dressing which stays in place when you go home, normally a few hours later. Your eye may begin to feel sore once the local anaesthetic starts to wear off. The pain isn’t usually too bad and you can take a painkiller tablet, such as paracetamol, to help. The dressing, which is put on in the hospital, usually needs to stay on your eye overnight, but you should be able to take it off the following morning. Your eye may look red and you might develop some bruises but these will improve over the next few days.

Immediately after the operation

Some people can tell that their sight has improved straight away. If your cataract was quite mild you might not notice a big change in your vision but if your cataract was quite bad you may be able to notice a bigger improvement. Either way, your sight may not be as good as you expect for the first week after the operation, as the eye is still recovering from the surgery and will probably be a little swollen.

Immediately after the surgery you will be given an anitbiotic and steroid eye drop combination to prevent infection and reduce inflammation simultaneously. It is important to take these drops as the ophthalmologist recommends and to complete the course. If you have problems using the drops you should let Dr Joseph know as he may be able to arrange some help for you, or alternative drops.

Most people have no problems after the surgery and they are up and about as normal the next day. If your eye is very painful or your vision suddenly gets a lot worse, then you should let Dr Joseph know as soon as possible as this may mean he needs to see you again.