Causes of blindness

An overview of the most common causes of blindness worldwide.

Symbolic photo: An overview of the most common causes of blindness. Credit: Ulrich Eigner

At least 75 percent of blindness is preventable. For many years now, LIGHT FOR THE WORLD has been working to reduce avoidable blindness. In most cases, treatment or prevention could be easy if sufficient resource were in place: by the timely administration of medication, by small routine operations, by prevention and education measures. However, many people still do not have access to treatment, medication or doctors.


is the world’s most common cause of blindness, affecting 65 million people worldwide. This clouding of the lens may occur due to age, injury or be congenital. Cataracts can be treated by replacing the cloudy lens with an artificial one in a 15-minute operation.


is the third most common cause of blindness. Glaucoma can be treated with medication and an operation, but is not curable.

River blindness (onchocerciasis)

is a parasitic disease which causes inflammation and bleeding that leads ultimately to blindness and other disabling effects. River blindness is on the retreat worldwide thanks to the widespread distribution of the drug Mectizan.


is the most widespread infectious cause of blindness, responsible for the visual impairment or blindness of about 2 million people. Repeated infections with the bacterium Chlamydia trachomatis cause the inside of the eyelid to scar, turn inward and painfully scratch the cornea, eventually leading to irreversible blindness. In its earlier stages, trachoma is treated with antibiotics and is preventable through improved hygiene and sanitation. In the final stage of the illness, referred to as Trachomatous Trichiasis, surgery on the eyelid is the only way to prevent the loss of sight.

Uncorrected refractive errors (URE)

About 124 million people are visually impaired due to uncorrected refractive error. In most cases, vision can be restored with spectacles. In Uganda, LIGHT FOR THE WORLD together with the Brien Holden Vision Institute has successfully initiated a National Programme giving poor people access to high quality, tailor-made spectacles.

Childhood blindness

Around 1 million children are blind and about 19 million visually impaired due to causes like uncorrected refractive errors, Vitamin A deficiency, cataract or injury.

Our goal

As part of the global initiative Vision 2020, Light for the World strives to eliminate preventable blindness altogether.