👁️ Special Senses🟡 High-yieldBlindness and Visual Impairment

Blindness: Definition and Causes

How blindness and low vision are defined by the level of sight, and the main causes worldwide, many of which are preventable.

Key points

Blindness is defined by how much sight remains, measured as the sharpness of vision and the width of the visual field.
The World Health Organization grades visual loss into categories of low vision and of blindness using these measures.
Worldwide, leading causes include cataract, uncorrected refractive error, glaucoma and diabetic eye disease.
A large share of blindness is avoidable, meaning it could be prevented or treated, such as cataract and refractive error.
In children, causes include vitamin A deficiency, infections and inherited disease, some of them preventable.

Memory trick

Blindness is graded by sharpness and field (WHO categories); the top causes are cataract, refractive error, glaucoma and diabetic eye disease; much of it is avoidable; in children think vitamin A lack, infection and inherited disease.

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👁️ Special Senses🟡 High-yieldBlindness and Visual Impairment

Blindness: Definition and Causes

How blindness and low vision are defined by the level of sight, and the main causes worldwide, many of which are preventable.

Key points

Blindness is defined by how much sight remains, measured as the sharpness of vision and the width of the visual field.
The World Health Organization grades visual loss into categories of low vision and of blindness using these measures.
Worldwide, leading causes include cataract, uncorrected refractive error, glaucoma and diabetic eye disease.
A large share of blindness is avoidable, meaning it could be prevented or treated, such as cataract and refractive error.
In children, causes include vitamin A deficiency, infections and inherited disease, some of them preventable.

Memory trick

All of Ophthalmology More Special Senses