Cataracts: an introduction

Cataract, the leading cause of blindness worldwide, refers to a condition where the lens of the eye becomes clouded or opaque (not transparent). The term cataract comes from the Latin word for waterfall, a word origin that is, no doubt, based on the white and opaque appearance of the lens of the eye, similar to the flow of turbulent water in a waterfall. Normally, cataracts develop and progress gradually in a person after the age of 60 years. However, in people with diabetes cataracts tend to develop earlier and progress more quickly. A person with diabetes may develop a cataract as early as age 30 and the condition may progress to the point of severe vision impairment very rapidly.1

What causes a cataract?

Our understanding of why cataracts form is incomplete. The cells that make up the lens of the eye are highly specialized. Unlike many structures in the body, where there is a process by which old cells are constantly being replaced, the old nonviable cells in the lens are not discarded. This makes the lens very susceptible to the effects of aging on the structure of the cells. Results from experiments suggest that cataracts may result from degradation of lens cells from continued exposure to light and other substances. In people with diabetes, some cases of cataract development have been linked to poorly controlled blood glucose.1

Are there risk factors for cataract development?

There are several known risk factors for development of cataracts in the general population. These include1:

  • Smoking
  • Age
  • Consumption of alcohol
  • Exposure to sunlight
  • Malnutrition
  • Physical inactivity
  • Metabolic syndrome
  • Diabetes mellitus
  • Use of systemic corticosteroids and prolonged use of inhaled corticosteroids

How can I reduce my risk for cataracts?

There are several steps you can take to decrease the likelihood that you will develop cataracts or to slow their development. If you smoke, try to quit as soon as possible. Additionally, you should moderate your consumption of alcohol. Protect your eyes using sunglasses or a cap with a visor from too much direct exposure to sunlight. If you have diabetes, it is especially important to control your blood sugar. Finally, healthy lifestyle modifications (including a diet rich in fruits and vegetables) and getting regular aerobic exercise can provide benefits for your general health as well as the health of your eyes.

What are the symptoms of cataracts?

Cataracts are associated with characteristic symptoms as they develop. These include1:

  • Dimming of vision
  • Reading difficulty
  • Need for brighter lighting (specifically while reading)
  • Driving difficulty (due to visual impairment)

What is the treatment for cataracts?

The only treatment option currently for cataracts is surgery to remove and replace the lens of the eye with an artificial one. Great advances have been made in cataract microsurgery over recent decades and, typically, intraocular lens implantation can restore normal vision. Surgery can typically be done on an outpatient basis, using only local anesthesia. During surgery, the lens capsule is left intact to hold the artificial lens in the proper position. In some instances, the capsule may later become clouded, requiring a follow-up laser surgery to make a permanent hole in the lens capsule.

Will it be necessary to use vision correction after cataract surgery?

Most artificial lenses used in cataract surgery are only able to focus at one distance, so it is often necessary to use glasses for reading, distance, or both following surgery. Newer artificial lenses are now under development that may allow focusing at multiple distances.

Written by: Jonathan Simmons | Last reviewed: May 2014.
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