Causes of Blindness in the UK

Loss of sight can occur as a result of disease, defect or injury; it may develop gradually or suddenly or be present from birth. Blindness is defined differently from country to country; in the UK, people are said to be blind if they are unable to perform any work for which eyesight is essential. Partial sight has no specific legal definition, but it is a lesser visual disability that can still affect a person’s lifestyle or employment. It is not the same as poor vision, which can be corrected with glasses or contact lenses.

Causes of Blindness

Blindness in the UK

Normal vision depends on light passing through the eye and reaching the light receptors in the retina; here, light energy is translated into nerve impulses that are sent to the brain via the optic nerve. Anything that blocks the passage of light or interferes with the nerve impulses can result in blindness.

The major causes of blindness worldwide are: cataract, the clouding of the internal focusing lens of the eye; glaucoma, nerve damage to the retina and optic nerve caused by high pressure within the eyeball; trachoma, a bacterial infection that causes scarring of the cornea and conjunctiva; onchocerciasis, which is a tropical disease of the skin caused by larvae of a parasitic worm; and conditions such as diabetes, which can cause damage to the retina, and dietary deficiency – corneal disease linked to lack of vitamin A, for example, is a major cause of blindness.



There are almost 200,000 people registered as blind in the UK and almost 160,000 registered as partially sighted – around 6 in every 10,000. But many blind and partially sighted people are not officially registered, and the actual number is estimated to be just over 1 million. Colour blindness is not really a form of blindness; sufferers, who are usually male, often have good vision but a reduced capacity to perceive various different colours.

Some diseases causing blindness affect different age groups. The majority of blind people are over 65 and have lost their sight as a result of a condition that develops in later life.

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