Complete vision loss or blindness refers to a severe loss or absence of vision. A person is considered legally blind (Vision Australia 2007):
- when they cannot see at six metres what someone with normal vision can see at 60 metres
- if their field of vision is less than 20 degrees in diameter (as a person with normal vision can see 180 degrees).
The term 'vision impairment' simply means a person has some degree of sight loss. Most people with vision impairment will have some degree of sight and may use a white cane, guide dog and/or a GPS navigating device to help them with their mobility (Vision Australia 2007).
Many diseases of the eyes, diseases of the body, or injury can result in blindness or vision impairment (MDA Internet 2005). Blindness or vision impairment may be present at or near birth (congenital) or develop later in life (acquired).
Further information on deafblind or dual sensory can be found through the following link:
Links to specific types of blindness or vision impairment