Visual impairment, also known as vision impairment or vision loss, is a decreased ability to see to a degree that causes problems not fixable by usual means, teaching visually impaired children as glasses. As of 2015 there were 940 million people with some degree of vision loss.
246 million had low vision and 39 million were blind. The majority of people with poor vision are in the developing world and are over the age of 50 years. A typical Snellen chart that is frequently used for visual acuity testing. The definition of visual impairment is reduced vision not corrected by glasses or contact lenses.
The World Health Organization uses the following classifications of visual impairment. 500 or a visual field of less than 10 degrees. 60 with normal fields of vision, or gross visual field restriction. Unable to see at 3 metres what the normally sighted person sees at 60 m. Not eligible to drive and may have difficulty recognising faces across a street, watching television, or choosing clean, unstained, co-ordinated clothing.