Aids for the Blind

a branch of special-purpose instrumentation concerned with the development of technical devices for the blind, the visually handicapped, and the blind-and-deaf—to facilitate their education, their polytechnical and industrial training and preparation for work, and their access to cultural and social services—as well as devices for the correction, improvement, and restoration of vision.

The technology of aids for the blind is based on the physiology of the higher nervous system, ophthalmology, the neurophysiology of vision, electrophysiology, physiological optics, the hygiene of vision, biotechnology, theories of instruction of the blind, and psychology—including general, engineering, and medical psychology and the psychology of the blind; it also draws on communications theory, electronics, and information theory.

Electronic engineering makes it possible for the blind to obtain objective and reliable information concerning objects, visual processes, and natural phenomena by some means other than sight. Various types of reading machines have been developed to give the blind access to books, magazines, and other general reading matter. These machines convert letters into acoustic, tactile, or tactile vibration signals that are reproduced either as sounds or as raised-dot or other embossed images representing letters, syllables, or words.

By converting visual signals into acoustic ones, special machines permit the visually handicapped to perceive surrounding objects, processes, and natural phenomena—for example, the outlines of mountains, buildings, and trees—whether close by or at a distance, as well as to obtain a variety of visual information in the course of laboratory and practical work in schools and other educational institutions. Various kinds of electronic devices with acoustic or tactile signal systems are available to help the blind orient themselves in space. Other aids include special canes for the blind.

Special typewriters and other devices enable the blind and the blind-and-deaf to write using the braille system. Tape recorders and specialized sound reception systems are also used.

Assorted lenses, projectors, and reading devices of varying magnifying power are available to those with defective vision. Schools for the visually handicapped employ closed television systems, which enable those with partial or defective vision to obtain audiovisual and visual information by means of intensified contrast, increased brightness, and enlarged images corresponding to the degree of vision impairment.

In restoring defective vision, various optical devices are used to develop visual acuity, color discrimination, binocular vision, and fixity of sight. The working blind and visually handicapped are provided with specialized equipment that increases their productivity and ensures labor safety and easier working conditions.

In the USSR, various scientific research institutes work on the development of aids for the blind—for example, the All-Union Scientific Research Institute of Medical Instrumentation, the Scientific Research Institute of Defectology of the Academy of Pedagogical Sciences of the USSR, and institutes for the study of eye diseases and for research on work fitness and the organization of labor for the disabled. Other countries that have research centers devoted to aids for the blind include Great Britain, the German Democratic Republic, the Polish People’s Republic, the Czechoslovak Socialist Republic, the United States, Sweden, Japan, and the Federal Republic of Germany.