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What is a Cataract?

A cataract is a cloudiness or opaque area that develops in the normally transparent lens of the eye. While most are age-related, they may also be congenital, metabolic or traumatic. 

Cataract Capture 2 .JPG

Types of Cataracts


The lens is composed of layers, like an onion. The outermost is the capsule. The layer inside the capsule is the cortex, and the innermost layer is the nucleus. A cataract may develop in any of these areas. Cataracts are named for their location in the lens, the most common being:

  • A nuclear cataract, located in the center of the lens. The nucleus tends to darken with age, changing from clear to yellow and sometimes brown.

  • A cortical cataract, affecting the layer of the lens surrounding the nucleus. The cataract  may look like a wedge or a spoke and appears white.

  • A posterior sub-capsular cataract,  found in the back outer layer of the lens. This type often develops more rapidly and often in a younger age group. 

Causes and risk factors

Most cataracts are due to age-related changes in the lens of the eye, however, other factors can contribute to cataract development, including:

  • Diabetes mellitus.

  • Drugs, such as:

    • Corticosteroids.

    • Chlorpromazine and other phenothiazine related medications.

  • Ultraviolet radiation.

  • Smoking. 

  • Alcohol. 

  • Nutritional deficiency. Although the results are inconclusive, studies suggest an association between cataract formation and low levels of antioxidants (for example, vitamin C, vitamin E, and carotenoids). 

  • Genetics

  • Previous eye surgery

Symptoms of cataracts include blurred or cloudy vision, double vision, haloes or glare around lights, difficulty with night vision or in bright light.​

If visual impairment interferes with your ability to read, drive, or do the things you enjoy, then you may want to consider cataract surgery. Cataract surgery is a relatively painless procedure in which a small incision is made near the cornea allowing for the insertion of a device that breaks up and removes the cataract,  a process called phacoemulsification.   A new artificial lens is then placed in the eye.

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