Cataracts in diabetes
Normally light enters the eye from the front, passes through a clear lens, and reaches the back of the eye so you can see.
If the lens becomes cloudy like frosted glass, light cannot pass through, and you cannot see properly. 'Cataract' is the name of the 'cloudy' human lens.
Think of a camera, with a lens that bends the light so that the light 'focuses' onto the film at the back. If this lens becomes scratched or greasy, it cannot bend the light in the correct direction, and the light is scattered in all directions. You may notice blurred or mis ty sight, see double, or notice colours appear much duller than they did previously.
top: a clear lens, no cataract. Light enters the eye directly
bottom: a cloudy lens = a cataract. Light entering the eye is scattered
A cataract will not damage your eye in any way. It can be operated on safely at any time, thick or thin. A cataract may change the focusing in the eye, and you may need new spectacles now and again. If you think you do, ask your optician or the doctor in the hospital eye clinic. But glasses themselves do not help you see better if you have a cataract.
Some cataracts get worse quickly, others slowly: most do get worse over months or years. If your sight gets worse very slowly, the cataract is only slowly becoming thick.
The thicker or cloudier the cataract becomes, the worse the sight. A doctor cannot predict with certainty.
Large print is naturally much easier to read, and a magnifying glass may help (see Coping with poor vision).
A good light may help, particularly an anglepoise light behind the shoulder.
Stronger glasses that mean you can bring books closer to your eye to make reading easier, and an optician (optometrist) can advise you.
You may notice great difficulty driving at night, when car headlights are shining into your eye. This may be so bad you have to stop driving at night, and at this stage, if you want to keep driving, you may need a cataract operation.
You may notice difficulty seeing in sunlight. Dark glasses may help, or a hat with a large peak. Eventually you usually need an operation.
Cataracts occur as people get older. They are much commoner if you smoke, whether cigarettes, cigars, or a pipe. They occur more often in diabetes, and they can run in families. Steroid tablets may help to cause cataracts if given at a high dose or for a long time. There are many other causes, including other types of eye disease and eye injury.
A cataract does not usually damage your eye in any way. A cataract in one eye cannot lead to any damage in the other eye, and you cannot use the good eye too much and damage it. Similarly, sit close to the television if this helps you see it better: this will not damage your eyes. A cataract often develops in the other eye, but many people only get one in one eye.
Many cataracts do get worse, especially if you are middle aged and have diabetes. Many people with diabetes do eventually need cataract surgery.
There is no specific diet or drug treatment for cataracts, but following UK Department of Health advice may help: a diet low in animal fat and salt, with five portions of vegetables or fruit a day, with 30 minutes exercise such as walking, and not smoking.
An operation to remove the cataract is usually the only way to make improve your sight. But before you can decide, you need to know the pros and cons of an operation. A cataract operation is generally safe, and with a surgeon who is experienced in cataract keyhole surgery, the risk of a serious problem is about 1%.
So in a way you are the best person to decide: certainly, if you cannot do what you want to do, such as read, watch TV, or walk in the street, an operation is usually helpful (if your eye has no other conditions.) Remember, many patients who have surgery are in their 80's.
Typically, you have the operation as a day case. You go to the hospital in the morning, and go home later that day. You have a local anaesthetic injection, wait for it to work, then have the operation which takes about 20-30 minutes. A key hole operation is often used: a small tube is inserted into the eye to suck the cataract out, and a plastic lens implant is put in its place. The plastic lens implant is placed in the 'capsule' of the cataract.
Routinely, the only major discomfort can be the local anaesthetic injection. At home, you have drops to put in, and routinely have one or two visits to the hospital, before seeing your optician for glasses. Normally after an operation, you see well.
However, if there are other problems in your eye, such as a damaged retina (the film at the back of the eye), your sight will not be so good. In diabetes the operation may make the retinopathy worse and laser may be needed. Often the ophthalmologist recommends laser before the operation to try and stabilise the retinopathy. (See page concerning your type of retinopathy.)
You usually do need glasses after an operation, because the implant cannot change its focus like a camera. You may need reading or distance glasses, or both.
Unfortunately a few people do develop problems. Without diabetes, there is 1 in 100 risk of severe complications such as needing a second operation, infection, etc. But in diabetes there is a slightly greater risk of such problems as
This is fluid collecting at the back of the eye, in the central area of the retina as in the diagram immediately below. This blurs the central vision. See.
macula oedema...fluid accumulating after cataract surgery, causing reduced central and detailed vision