Vision Impairment

What do we mean by 'vision impaired' ?

There are various definitions which describe this disability, but in simple terms it could be:

• Partially sighted - a person can see but with some difficulty;
• Low vision - a more severe impairment of vision, but not necessarily limited to distance vision. This would be someone with sight who is unable to read a newspaper at a normal viewing distance, even with the aid of eyeglasses or contact lenses;
• Blind - a person having no useful sight.

How does someone with a vision impairment use a computer ?

This is where Assistive Technology (AT) comes into play.  Dependent on the severity of the impairment, there are a number of products available or computer adjustments that can be made, which allow you to use a computer more easily.

Those with partial or low vision:

• Increasing the screen resolution - Windows display options
• Larger monitor
• Larger fonts - making them easier to see in Microsoft Windows
• Different background colours - Choosing your preferred colours in Windows
• Magnification
• Magnification with speech software
• Screen overlay sheet or lens - called a 'Fresnel'. 

  http://en.wikipedia.org/wiki/Fresnel_lens

  http://science.howstuffworks.com/question244.htm

  http://www.pa.uky.edu/sciworks/physicspettingzoo/Fresnel.htm

• CCTV viewer, which projects magnified printed material onto a monitor

Those with no useful sight:

• Braille displays and keyboards
• Braille embossers
• Screen reading software 

Products in practice

This is a novel way to use a Fresnel lens !

Using a screen reader.  This is a free one called 'Thunder'. 

Using AT - overcoming Low/No vision difficulties.

Using a screen magnifier - in this example, 'ZoomText'.

Useful Resources 

• RNIB - Access Technology factsheet

• Assistive technology videos - useful search Tags (YouTube): assistive / disability / magnifier / ZoomText / macular

• ICT Hub. Open Source Accessibility Guide for adjusting Linux-based Gnome desktop settings 

• Guide Software - useful video on what it does, how it works