What is a cataract?

    

Normal                            Cataracts

A cataract is a clouding of the normally clear and transparent lens of the eye.

When a cataract develops, the lens becomes as cloudy as a frosted window, and light cannot be properly focused on the retina, resulting in an unclear image. Often, only a small part of the lens is affected and, if sight is not greatly impaired, there is no need to remove the cataract. If a large portion of the lens becomes cloudy, sight may be partially or completely lost until the cataract is removed.

Depending on the size and location of the cloudy areas in the lens, a person may or may not be aware that a cataract is developing. If the cataract is located on the outer edge of the lens, no change in vision may be noticed, but if it is located near the centre of the lens, it usually interferes with clear sight.

Cataracts related to ageing are the most common type, but cataracts can also result from hereditary factors, diseases, medications or injury. Although it's rare, cataracts also can affect children and young adults.

What are the signs or symptoms?

• Blurred or double vision, ghost images, or the impression of a "film" over the eyes
  
  
• Problems with light (too much or too little), sensitivity to bright light and glare
  
  
• The need for frequent changes of eye glass prescriptions - none of which seem to help.

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