anne fiona spencer DM FRCS(Glasg) FRCOphth FCOptom
glaucoma surgery

Cataract information

What is a Cataract?

A Cataract is clouding of the lens in the eye that affects vision. Most cataracts are related to aging, and by age 80, about 50% of people will have developed a cataract.
Cataracts may be caused by factors other than aging: for example they may form in people who have had eye surgery, or as a result of diabetes, and as a result of steroid use. Cataracts may develop following eye injury, or trauma, though often not until years later.
Congenital cataracts: Some babies are born with cataracts or develop them in infancy. They may not affect vision, but if they do, the lens may have to be removed under the care of a specialist paediatric ophthalmologist.

What causes cataracts?

The lens lies behind the iris and pupil. It focuses light onto the retina at the back of the eye so enabling us to see a clear image. It also adjusts the eye's focus, called accommodation, enabling us to see things close to as well as at a distance.
The lens is made up of protein and water and as we age the protein may clump and start to cloud, reducing the light that enters the eye. The cataract will slowly worsen and as it does so, vision will become blurred and dulled. The lens will become a yellowish/brownish colour as the cataract develops, causing colours to dull and the ability to distinguish between dark colours may become difficult.In some people the posterior part of the lens develops focal opacities which reduce vision more quickly and cause increasing glare and difficulty with reading.

People can develop cataracts in their 40s and 50s but they are usually mild and don't affect vision. It is mostly after the age of 60 that cataracts become noticable.

What are the risk factors for developing a cataract?

Certain diseases such as diabetes are associated with earlier cataract development. Environmental factors such as prolonged exposure to sunlight as ultraviolet light is a risk factor. Smoking may be associated with earlier cataracts.

What are the symptoms of a cataract?

The most common symptoms of a cataract are:
Cloudy or blurred vision.
Colours appearing faded or browner, particulularly blue colours are reduced.
Glare: Headlights, lamps or sunlight may seem too bright. A halo may appear around lights.
Poor night vision.
Double vision or multiple images in one eye may occur as the cataract gets denser.
Frequent changes to the prescription for your spectacles or contact lenses.
These symptoms may be due to eye problems other that cataracts, so you should always check with an eye professional.

How is a cataract detected?

A cataract is detected by an eye examination which includes a number of tests:
Visual acuity test. This measures how well you see at various distances.
Dilated eye examination. Drops are placed in the eye to dilate the pupil and enable the optometrist or ophthalmologist to examine the optic nerve and the back of the eye for signs of damage or other problems.

How is a cataract treated?

The symptoms of an early cataract may be improved by new spectacles, brighter lighting, glare-reducing sunglasses or magnifying lenses. If none of these measures help then surgery is used to remove the lens and replace it with an artificial one.

If you cannot perform normal everyday tasks such as driving, reading, watching TV you may wish to consider surgery. You will make the decision together with your eye care professional, and once you understand the benefits and risks of the surgery, you can make an informed decision about whether you want to go ahead. Delaying the surgery until you feel ready to undertake the small risks involved will not result in long term damage to the eye or make the sugery more difficult, so you can take time to decide.

Sometimes other eye problems may make it advisable to remove a cataract, for example, if the cataract prevents assessment or treatment of another eye problem such as macular degeneration, glaucoma or diabetic retinopathy.

If you wish to consider surgery, you will be referred to a ophthalmologist, a specialist in eye surgery. If you have cataracts in both eyes then surgery will be done separately, probably a few weeks apart.

In many instances, even if your eye professional does find a cataract, it does not mean you will necessarily need surgery as it may be several years before you develop significant problems with your vision.