Feature

Reading for the Blind

New technology is opening up communication possibilities for blind and visually impaired people.

By Steven J. LaGrow and Simon M. Leung

Over 30,000 people in New Zealand cannot read newsprint because they are visually impaired; around 9,000 of these cannot read any standard print without assistance. This can present major disadvantages in the "information age".

Fortunately, the vast majority of visually impaired people are able to read with only minor adaptations needed. Most, for example, can read print if it is of sufficient size, and developing technology is presenting a variety of ways in which print size can be enlarged.

Type can be physically enlarged when printing. What was once a special run at a printery can now be produced simply by changing fonts, increasing the standard 8- or 10-point letters commonly used to practically any size. Print size can be further enhanced with photocopiers. Most photocopying systems will enlarge originals by at least 1.5 times, and further enlargements can be made.

Although there are few limits to the size of print we can produce, there are limits to the benefits obtained. Even though reading rates will initially go up as print size increases, they will stabilise and then decline after an optimal point has been reached. This occurs when the advantage of clarity is overwhelmed by the disadvantage of an ever-decreasing amount of information, such as the number of words or letters, contained in the available visual field.

Print may also be enlarged by simply moving it closer to the eye, a phenomenon known as relative distance magnification (RDM). Each time the distance from the eye to the object is halved, the object appears to double in size. People can obtain quite a bit of magnification from this method, but they have to be able to focus at close range. They can be helped in this by use of a simple convex lens, such as those found in a standard magnifier.

The amount of magnification which can be obtained this way is generally limited to 10 or 12 times. At that level, the distance between the eye and what is being read is very short, and the field of view very limited. Greater magnification can be obtained through the use of specially adapted telescopes known as telemicroscopes.

Telemicroscopes are telescopes with a relatively strong convex lens, or reading cap, added to the system's objective lens. The telescope enlarges the image and the reading cap makes it possible to use at short range. Telemicroscopes allow for higher power and more normal reading distances than available from a simple magnifier.

Electromechanical
Magnification

Print size may also be enhanced through electromechanical means such as closed circuit television (CCTV) systems and home computers.

The CCTV system consists of a camera, a monitor and an x-y table. The camera has a zoom lens and a light source, and is used to capture images from material placed on the x-y table; the monitor can then display the print. Print may be enlarged by as much as 60 times with this system.

Software packages can increase the characters displayed by computer monitors as much as eight times its normal size. This allows almost any computer monitor to be used as a reading aid, and is becoming increasingly common. Many books, journals and magazines are now available on disk, and those that are not available can be scanned for entry.

Accessing printed material visually is not always the most efficient option. Those using the very high power of magnification of a CCTV system, for example, often find their reading rate to be too slow to complete many tasks competitively. Others may not be able to read print regardless of the level of magnification available. Thus, these people find that they must rely on either touch or hearing to meet their reading needs.

Braille

Braille is the most common tactile reading system, using a series of embossed dot arrangements. Each character, or cell, uses different number of dots in various configurations. Sixty-three possible combinations can be formed, representing the alphabet, numbers, punctuation marks, and letter groups. In order to save space, 189 contractions are used to stand for whole words or parts of words.

Grade one Braille is the uncontracted form, used mainly for labelling and simple notes. The contracted form, grade two, is used for more extensive reading and writing. Braille is still the only complete system that enables a blind person to both read and write. It is written, or rather embossed, with a mechanical Brailler or manually using a slate and stylus. Nowadays, electrical and electronic Braillers are also becoming more and more widely used. Software packages can convert print to Braille for permanent use or on computer displays.

Unfortunately, Braille, especially in the contracted form, is a fairly complex system that requires considerable time and effort time to learn. The reading speed is relatively low -- about 100 words per minute for highly proficient users, and as low as 20-30 words per minute for adult learners. Average print readers, in contrast, have a reading speed of 250-300 words per minute.

In addition, Braille is not always readily available, as a specialised transcription service is required. It is also very bulky -- a pocket-sized dictionary transcribed into Braille would occupy about the same volume as an entire set of Encyclopedia Britannica. Nevertheless, in its 160 years of history, Braille has enabled innumerable blind people to attain educational and professional achievement, and it definitely has an important place in the personal development and practical daily life of a blind person.

A further way for a visually impaired person to access information is through hearing, by having the information read or recorded and using readers, taped material and/or synthesised speech. Synthetic speech uses computerised production of phonemes formed into words based on a number of programming formats. It can be produced by home computers, "reading machines" which scan printed material, and "talking" typewriters, calculators, and clocks.

The major advantages of readers, human or machine, are speed and ease of use. A normal oral reading speed is 150-175 words per minute. However, the playing speed of recorded speech can be increased to as high as 300 words per minute using special compression devices. Such variable speed control enables enhancement of reading speed without a "Mickey Mouse" effect and no significant loss in comprehension. Recording devices are relatively easy to set up and use, and allow visually impaired people to listen to material ranging from novels, to recipes, to textbooks.

Computer Assistance

Technological advances based upon the microchip have significantly enhanced the quality of life of people with visual impairment. Microcomputers, word processing software, and a variety of computer peripherals offer these people a complete reading and writing system which can also be used to interact directly with most sighted people.

The visually impaired person can access a computer through its keyboard, as does any other user, and Braille terminals are available. However, it is the accessibility of the output that makes computers and their ancillary aids revolutionary. Such accessibility is provided by synthetic speech systems, screen display magnification software, and Braille translation and output systems which can provide printed copy or screen displays.

Speech output is available through an internal speech card or by using an external voice synthesiser and speech software. Whatever appears on the screen will then be read out to the visually impaired user. The quality of the synthesised speech and capacity for navigating across the screen for desired information depends on the sophistication -- and price -- of the hardware and software.

Screen magnification systems cater for the needs of low-vision people, increasing the normal screen display to a clearly visible size. In addition, levels of contrast and brightness can also be adjusted to suit the particular eye conditions of the individual.

Refreshable Braille provides a single line of electronically displayed Braille by means of metal pins that pop up in the same configurations as the Braille characters. After reading one line of text (normally either 40 cells or 80 cells), the press of a key will "refresh" it, producing a new line. Thus the blind computer user can review whatever is on the screen line by line at his or her own pace. If a permanent copy is desired, a Braille embosser can produce this, translated in appropriate Braille code, in much the same way as a normal printer.

Each device has advantages as well as limitations, and a combination is often used for different purposes. A user may adopt speech output for fast "reading", and Braille or large-print output for detailed review or scrutiny.

Computer technology is having a tremendous impact on Braille production as well. A traditional mechanical Brailler could take a year or longer to transcribe a 300-page textbook. Nowadays, making use of translation programmes, the same task can be shortened to less than a month. If optical character recognition is used to enter text into the computer, transcription can be done in a week. If the text is already stored on disc -- increasingly common in computerised publishing -- then the same book could be transcribed within a couple of working days.

This was hardly imaginable ten years ago, and undoubtedly makes a great difference in meeting the educational and occupational demands of people who are visually impaired. It appears that we are now entering an era where visual impairment will no longer pose a great disadvantage for accessing information.

Professor Steven LaGrow and Dr Simon Leung are in Massey University's Rehabilitation Studies Section.
Professor Steven LaGrow and Dr Simon Leung are in Massey University's Rehabilitation Studies Section.