According to the International Classification of Diseases, visual function is classified into four main categories:
- Normal vision
- Moderate visual impairment
- Severe visual impairment
According to recent estimates from the World Health Organization (WHO), the leading global causes of eye disease, known as moderate to severe visual impairment, are:
- uncorrected refractive errors: 53%
- unoperated cataracts: 25%
- age-related macular degeneration: 4%
- diabetic retinopathy: 1%
And the main causes of blindness are:
- unoperated cataracts: 35%
- uncorrected refractive errors: 21%
- Glaucoma: 8%
81% of people with blindness or moderate to severe visual impairment are over 50 years old and approximately 1.4 million children under 15 years old suffer from irreversible blindness and need access to visual rehabilitation services to optimize their functioning.
Refractive errors are very common vision disorders, in which the eye cannot focus images. The result is blurred vision, which is sometimes so severe that it causes visual impairment. The most common are:
- Short-sightedness: difficulty seeing distant objects clearly
- Far-sightedness: difficulty seeing nearby objects clearly
- Astigmatism: distorted vision due to abnormal curvature of the cornea
- Presbyopia: difficulty reading or focusing well at an arm’s length. It is associated with aging and affects almost everyone.
Refractive errors cannot be prevented, but they can be diagnosed during an eye exam and treated with corrective glasses, contact lenses, or refractive surgery.
Get a check-up and correct any visual abnormality you have in time.