MD Functional Limitations
The functional limitations of MD in general include; fluctuating vision, problems reading, and limited night vision. The impairment causes blurred central vision and limited night vision that can create difficulty in driving, reading or discerning fine detail. It can also affect color vision particularly with reds and greens.
A person with MD might need to use a book with large print in order to read, view objects through a magnifying glass, or need larger fonts and text for their computer. People with MD often look to the side of an object instead of directly at it (eccentric viewing). They often cannot recognize faces. MD affects the quality of life as people quit traveling, driving, shopping, reading, watching TV or using a computer as they try to cope.
Low vision aids are often used to help compensate for MD. Some of those adaptive technologies used for this impairment include:
• Magnifiers – The four types of magnification include: relative-size, relative-distance, angular and projection
• Large print fonts and displays
• Proper lighting - lamps and lights with various types of illumination may enhance the visibility of the working surface.
• Good corrective glasses (biotic glasses)
• Special paper and writing aids
• Adaptive appliances like for low vision like clock or calculators with voices
• OCR software
• Video enlargement systems
• Computer display enlargement systems
• Computer speech software
• Material positioning devices-page holders, book holders, or book stands, and slantboards enable better positioning of the material to decrease distance, angle or glare.
• Audio support-software or hardware that gives information through auditory channel in addition to the primary channel whether it be visual or tactile.
• Text-to-Speech- software that converts digital text into audio. It is implemented in
talking programs, like word processors, or is part of read aloud imported text.
• Portable reading devices- Hardware that supports various formats of audio text.
Information may be stored either as audio files on media cards, or as soundtracks on
CDs.
• Large print keyboard stickers – in order to make the keyboard labels more visible
stickers with large print characters can be used. They come in two color versions –
white on black, or black on white.
• Built-in magnifier (PC), Zoom (Mac) – computer operating systems come with
magnification accessibility features.
• Third party magnification software – a full-fledged application that increases the size
of screen content.
• Third party combo magnification and screen reading software – combines features of
screen magnifying software and speech output software giving dual-mode access to
computer information.
• Monocular-an optical device used for close-ups of distant objects. It may be used
in classroom to read more for or presentation projected on large screens.
• Specialized lighting – lamps and lights with various types of illumination may
enhance the visibility of the working surface.
• Large print or magnified screen typing instruction software/programs to assist in
keyboard instruction.
• lightbox-a device that provides a lighted working surface to give higher contrast
or attract visual attention.