A cataract is a progressive, painless clouding of the natural, internal lens of the eye. Cataracts block light, making it difficult to see clearly. Over an extended period of time, cataracts can cause blindness. They're often related to growing older, but sometimes they can develop in younger people.
Most cataracts develop when aging or injury changes the tissue that makes up your eye's lens. Some inherited genetic disorders that cause other health problems can increase your risk of cataracts. Cataracts can also be caused by other eye conditions, past eye surgery or medical conditions such as diabetes.
The underlying mechanism involves accumulation of clumps of protein or yellow-brown pigment in the lens that reduces transmission of light to the retina at the back of the eye.Diagnosis is by an eye examination
Cataracts are most commonly due to aging but may also occur due to trauma or radiation exposure, be present from birth, or occur following eye surgery for other problems.Risk factors include diabetes, smoking tobacco, prolonged exposure to sunlight, and alcohol.The underlying mechanism involves accumulation of clumps of protein or yellow-brown pigment in the lens that reduces transmission of light to the retina at the back of the eye.
Types of cataracts
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Nuclear sclerotic cataract
The most common type of cataract. The centre portion of the natural lens of the eye – the nucleus – becomes yellow and hardens.
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Cortical cataract
A less common form of cataract that appears as a cloudy opacity in the cortex, the outer part of the lens.
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Posterior subcapsular cataract
These cataracts form as opacities on the back surface of the lens. They cause light sensitivity, problems with reading vision and glare.