The world of the visually impaired can be a bit of a mystery if you’re not affected by it, or don’t know anyone who is. But if you’re in business, you may come across visually impaired people as employees or customers, so it helps to know some basic terminology.
Follow our A-Z tour of the land of the blind and you’ll know pretty much everything there is to know about sight loss.
Albinism – a condition in which people have little or no pigment, which leads to light hair and skin colour and worse than average eyesight. Most people with albinism have nystagmus, which causes rapid eye movement, extreme short-sightnedness and difficulty in focusing.
Blindness – Under World Health Organisation guidelines, a person can be registered blind if their sight level is 20/200. This means that while people with full sight can read text positioned 200 metres away, a person registered blind can only read text that’s 20 metres away or less. In feet, it’s 6/60.
Cataracts – a cloudy film that appears over the lens of the eye, which blocks light and gradually reduces sight. Cataracts needs to be operated on for sight to be restored.
Daltonism – a term used to describe colour-blindness, named after John Dalton, the 18th-cenetury chemist and physician who first identified it. The colours most often confused in colour-blindness are red and green
Eye – the eye is a delicate part of the body, but people who lose an eye can still see perfectly, though their sight may be a little flat and one-dimensional.
Feach – an Irish organisation which offers support to parents of blind and visually-impaired children, www.feach.ie
Glaucoma – a common cause of blindness. It occurs when pressure builds up in the eye, causing damage to the optic nerve. Early detection is crucial to ensure sight is saved.
Hospital – Many visually impaired people are still treated in dedicated eye and ear hospitals, such as the Royal Victoria in Dublin.
Iris – there is a condition called coloboma of the iris in which a person is born with a hole in their iris which causes blurred vision and even ghost images. Some eye conditions also cause the iris to lose its colour, such as albinism.
Jaws – a screenreader software which enables blind people and those with very little sight to use computers. It uses a voice synthesiser to call out the items on screen and the user navigates using keystrokes.
Keller – Though blind and deaf, Helen Keller learned to communicate through a sign language system developed by her teacher Anne Sullivan, herself visually impaired. Helen went on to earn a BA degree and campaign for various causes.
Lenses – artificial lenses can restore sight through surgery, or even with simple contact lenses.
Macular Degeneration – another common cause of blindness, especially in older people. It causes a deterioration in central vision, the vision we use to read, write, watch television and drive
Night Vision – in some eye conditions, night vision is compromised, making it difficult for people to see when it’s dark.
Optic Nerve – the nerve that transmits messages from the eye to the brain. If the optic nerve is malformed or damaged in any way, it leads to sight loss.
Partial Sight – also called low vision. There are varying definitions of partial sight, but generally it refers to sight problems that cannot be completely corrected by glasses.
Questions – when you or your child is newly diagnosed with sight loss, you’re bound to have a lot of questions. Fortunately, there are plenty of health professionals and organisations on hand to answer them.
Retina – this is a light-sensitive area of the eye which captures images from the world around us and sends them to the brain to be processed. Sight loss occurs when this is detached, or blood vessels burst behind it as a result of diabetes.
Symbol Cane – this is a short cane used to indicate that someone is partially sighted. It can be used to encourage motorists to slow down, or to indicate that someone needs assistance.
Test – a simple eye test at your local opticians can prevent sight loss. Tests are also a regular part of a visually impaired person’s life when they’re first diagnosed, or when they’re children.
Usher Syndrome – a condition that causes deafness and also leads to retinitis pigmentosa, in which a person’s field of vision gradually narrows and night vision is greatly reduced.
X-Ray – these are used to take images of the back of the eye and can detect blood-vessel damage.
VoiceOver – the screenreader built into Apple computers, iPhones and iPads.
Windows Magnifier – Windows 7 has greatly advanced the built-in magnifier options available to users. This post would have been somewhat harder to write without it.
Yellow – Scientists have discovered that by eating yellow or red vegetables, you can delay the onset of age-related macular degeneration.
Zoomtext – Magnifier software that makes a screen bigger and clearer, It allows you to contrast colours and increase the size of the mouse or cursor. It also offers voice commands. Similar packages include Lunar and SuperNova.