Cataract

A Cataract is a clouding of the eyes lens that causes loss of vision. The lens of the eye focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eyes focus so vision can be clear. As the Cataract gets bigger and clouds more of the lens (called ripening), it makes it difficult to read and do other normal tasks. For people with a ripe Cataract it is like trying to see through a waterfall.

Causes

The lens of the eye is made of mostly water and protein. The protein is arranged in a way that keeps the lens clear and lets light pass through it. A cataract forms when some of the protein clumps together and starts to cloud an area of the lens. A cataract won't spread from one eye to the other, although many people develop Cataracts in both eyes.

There are several causes of Cataracts , including:
  • Aging - protein in the lens changes from wear and tear (the most common cause)
  • Smoking
  • Diabetes
  • Infection
  • Injury
  • Exposure to radiation
  • Taking adrenal cortical hormones for a long time
  • Excessive exposure to sunlight
  • Birth defect

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.
  • Age: After age 60, most cataracts cause vision loss
  • Exposure to UV-B radiation from sunlight
  • Family members with cataracts
  • Diabetes

Symptoms

When a Cataract is small, you may not notice any changes in your vision. Cataracts tend to grow slowly, so vision gets worse gradually. Some people with a Cataract find that their close-up vision suddenly improves, but this is temporary. Vision is likely to worsen as the Cataract grows.

Symptoms include:
  • Cloudy or blurry vision
  • Problems with light, including:
  • Headlights that seem too bright at night
  • Glare from lamps or very bright sunlight
  • A halo around lights
     
  • Colors seem faded
  • Poor night vision
  • Double or multiple vision (this symptom often goes away as the cataract grows)
  • Frequent changes in your eyeglass or contact lens prescription
These symptoms can also be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.

Diagnosis

Although you might think you have a Cataract the only way to know for sure is by having an eye examination. To detect a Cataract an ophthalmologist or optometrist examines the lens and may do other tests to learn more about the structure and health of your eye.

A comprehensive eye examination usually includes:
  • Visual acuity test – an eye chart test that measures how well you see at various distances
  • Pupil dilation – the pupil is widened with eyedrops to see more of the lens and retina
  • Tonometry – a standard test to measure fluid pressure inside the eye; increased pressure may be a sign of glaucoma

Treatment

If you have a Cataract you may not need Cataract surgery for several years. In fact, you might never need Cataract surgery. For an early Cataract vision may improve by using different eyeglasses, magnifying lenses, or stronger lighting. If these measures don't help or if vision loss interferes with your everyday activities, such as driving, reading, or watching TV, surgery is the only effective treatment. In most cases, waiting until you are ready to have Cataract surgery will not harm your eye. If you have Cataract in both eyes, the doctor will not remove them both at the same time. They will have to be done separately. In most Cataract surgeries, the lens that is removed is replaced by an intraocular lens (IOL). An IOL is a clear, plastic lens that requires no care and becomes a permanent part of your eye. An ophthalmologist performs cataract surgery. In about 90% of cases, people who have cataract surgery have better vision afterward.

Prevention

It is not yet clear how to prevent Cataracts. But since vision problems increase with age, if you are over age 60, you should have an eye examination at least once every two years.