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Assistive products for people with blindness and visual impairment

Operating a computer, using the Internet, reading content and orienting oneself are central prerequisites for informing oneself, communicating and being mobile. Modern information and communication technologies as well as digital media can be used to support the equal participation of visually impaired and blind people in school, job and social life.

For a compact overview, exemplary assistive products are described here with a focus on computer hardware and software as well as electronic assistive devices.

The range of assistive products is wide, but some product features are typical or worth mentioning, such as.

  • large numbers or letters
  • large, illuminated displays
  • speech input and output
  • tactile marking points (Braille)
  • guiding lines and edges
  • two-senses principle of accessibility (acoustic and vibrating / tactile alarm signals)
  • Ultrasound or GPS (Global Positioning System) for orientation
  • RFID technology (Radio Frequency Identification) for labelling or product recognition

Braille printer (Braille printer): Braille printers punch Braille or graphics onto special paper. The braille paper is much thicker and more robust than conventional paper for usual printers. This makes information tangible and thus readable for people with blindness who can read Braille. Special conversion software converts files to the braille character set. There are double-sided braille printers with continuous paper or small, handy braille printers with single sheet feed for mobile use.

Braille displaysBraille displays output the screen contents in Braille, which can be read with the fingertips by means of pins of different heights. The displayed section can be moved and corresponds approximately to a DIN A4 line. A screen reader is required as a bridge software between the output medium and the computer. Usually a combined speech output is also used on the computer. With a braille display, one can usually only read the screen content, but not enter any data. Larger, 80-digit Braille displays are suitable for stationary workplaces, whereas smaller and mobile Braille displays with 12, 20 or 40 modules are preferably used for mobile work such as with a notebook.

  • Braille notetakersBraille notetakers are smaller devices for mobile use. They are equipped with speech input and output as well as Braille input and output, alternatively also with a laptop keyboard for text input. They have the usual interfaces and data connections as well as a standard operating system and can be synchronized with the PC system.

Reading systems (character readers, reading intercoms): Braille readers scan paper documents such as books, articles or invoices and store them in a file. A text recognition software (commercially available OCR Optical Character Recognition - software or special scanner software for the blind) processes the data, which is then played back by the speech output. Optionally, the person can also read the text with a Braille display or print it out in Braille if a Braille printer is also connected to the system.

A distinction is made between closed and open systems:

  • Closed reading systems are compactly manufactured devices that contain all components from scanner, text recognition software to voice output. The functions are distributed over a small number of easy-to-touch controls, making them easy to operate. The output is done by speech output or Braille display. Some closed devices store the scanned texts. Closed reading systems are especially suitable for people with late blindness and replace the use of a computer.
  • Open reading systems are usually used in the workplace on a standard PC in combination with a scanner, text recognition software and the reading software. In contrast to closed systems, open reading systems only output the scanned documents by voice. The data can be saved and further processed with conventional word processing programs. The system can be controlled via the computer keyboard.

Large character keyboards: These keyboards for people with visual impairments have high-contrast and larger lettering and sometimes tactile markings.

Screens: Large monitors with a screen diagonal of at least 20 inches and high screen resolution (display size of pixels) are important for people with visual impairments, especially if they use magnification software. In addition to monitor size, brightness and contrast, mirroring properties and adjustability to personal requirements are important.

Screen readerThe screen reader is a complex screen input and readout software that controls screen contents. The software interprets the screen information (e.g. texts, graphics and their meaning, the current input position or the screen layout) and outputs it tactilely via Braille displays or acoustically via voice output. There is external screen reader software installed on the PC (e.g. JAWS) as well as integrated screen readers. For example, TalkBack is Google's screen reader on Android devices, and VoiceOver is built into iOS devices. Screen readers also help people use large portions of standard software independently. However, not every computer program can be operated with a screen reader, for example due to poorly adapted software. Application training is therefore recommended.

Magnification softwareFor people with visual impairments, there is screen magnification software that not only displays screen contents larger, but also, for example, enhances contrasts and colours and tracks the focus (e.g. ticker, document reading function). Different output media (e.g. speech output, Braille display) can be combined with the software. Information that is not visible in the magnified image section is thus available, which is easier on the eyes.

Speech output: Speech output reads text aloud on the PC screen. A speech output is an integral part of a reading aloud system or screen reader that enables orientation on the screen. Speech speed, volume, pitch and sentence melody can be individually adjusted. Speech output is available as stand-alone software (e.g., for converting text on a computer screen or smartphone display to speech, reading aloud text messages and emails on a cell phone). These standardized announcement and read aloud features are not developed specifically for people with visual impairments, but are often intended for mobile use (e.g., driving).

Text and object recognition software (character reading software): Text recognition software (often called OCR software - Optical Character Recognition) identifies letters in a document or in graphic files such as PDFs, photos or scans and converts them into digital text files. The text files can be further edited or copied. The output of the text files is usually done in combination with computers and mobile devices via screen reader software (e.g. via speech output). Usually scanners (e.g. flatbed scanners) transfer the written documents. Smartphones are also suitable for occasional scanning. Object recognition software, on the other hand, compares photos or codes such as barcodes with a database and outputs the descriptions stored for them. This makes it possible, for example, to recognize products and, in some cases, faces.

Voice recognition softwareSpeech recognition software can automatically convert speech into text that appears directly on the screen. Speech recognition software can also be used to control computers and other devices. However, depending on the degree of visual impairment, speech recognition is only useful in conjunction with other assistive products such as Braille displays, screen readers, magnification systems, or speech output. In mobile devices with the operating systems Android and iOS, own speech recognitions are integrated.

AppsFor mobile devices such as smartphones or tablets, there are numerous, often pre-installed apps (applications for small displays and touch screens) that are also helpful for people with visual impairments and blindness. Examples include apps for recognizing text, barcodes, colors, light, or bills. Native apps are tailored to the computer's operating system (e.g. iOS, Android). Web apps run platform-independently in the respective internet browser and should support the other assistive products needed (e.g. screen readers) well. You can search for more apps in the App Store (iOS) and Google Play (Android) in our app search.

Other software for people with visual impairments: Other special software programs for people with visual impairments can only be operated via the keyboard using direct input commands and menus. The software range includes accessible currency converters, email clients, accessible database software or administration programs for electronic files and other document management systems.

Magnifying vision aids assist people with visual impairment in reading and spatial orientation when glasses or contact lenses are not satisfactory. However, as the magnification increases, the section of the image displayed becomes smaller.

Optical vision aids: Optical vision aids magnify information on paper or displays at near and far distances for people with visual impairments. They are usually used when magnification and contrast requirements are not so high and when reading shorter texts. Depending on the type, magnification of up to 12x is possible.

  • Optical vision aids for the near rangeThese include, for example, magnifiers, magnifying glasses and lenses. For example, there are magnifiers and stand magnifiers with illumination or large-screen magnifiers that are placed in front of a TV screen. Screen glasses for the workplace are adapted visual aids for activities at the computer when normal reading or varifocals or contact lenses do not meet the visual requirements. The distance to the monitor is adjusted to about 50 to 70 cm for screen glasses. Often the employer pays the full cost of the monitor glasses as part of its obligations under occupational health and safety legislation.
  • Optical vision aids for the distance range: These are, for example, binoculars, telescopes and telescope glasses. Telescopic glasses or monoculars (pocket telescopes) facilitate orientation in unfamiliar surroundings (e.g. reading street signs or display boards from a greater distance). Telescopic magnifying glasses (telescope glasses with clip-on magnifier) can facilitate reading.

Electronic visual aids: Electronic vision aids magnify information from paper documents or writing tablets on stationary or mobile devices. They can often display different contrasts (light-dark, colour) and, in some cases, text recognition, making them suitable for people with severe visual impairment. Depending on the model and monitor size, magnification of 5 to 60 times is possible.

  • Screen readersElectronic screen readers, also known as camera reading systems, record text excerpts (e.g. written documents, books) and transfer them to a screen at a high magnification. They can also be useful in the case of increased contrast requirements. Screen readers are available for close-up and/or long-distance reading (with remote camera), for example for recognising the content of PowerPoint presentations or on blackboards. A distinction is made between stationary, portable and mobile, small screen readers.
  • Electronic magnifiersElectronic magnifiers are battery-operated screen readers in pocket format for mobile use. They magnify much more than handheld optical magnifiers.

Cordless landline telephones and mobile phones (cell phones): Landline telephones and mobile phones adapted to the sensory impairment have, for example, tactile large keys, high-contrast displays, memory functions for direct dialling, voice control, screen readers for voice output or output via a connectable Braille display as well as magnification software with the option of connecting Braille displays. The software must be compatible with the telephone device.

Smartphones: Smartphones are the equivalent of small computers that can be used to make phone calls. They offer a variety of pre-installed or optional accessibility features such as zoom, screen reader, speech output or text recognition. You can find out more about the accessibility of mobile phones and smartphones here.

Audio players (DAISY players)DAISY is the worldwide standard for navigable multimedia documents (Digital Accessible Information System). DAISY players can be used to play audio files such as DAISY audio books in compressed mp3 format or to read documents such as newspapers. The devices are equipped with voice output and offer navigation and setting options so that you can turn pages, jump to chapters or adjust the reading speed. As an alternative to DAISY players, you can download free software to your computer and listen to the DAISY content. An overview of libraries for the blind with Daisy books can be found here: Mediengemeinschaft für blinde, seh- und lesebehinderte Menschen e. V..

Electronic reading devices (e-book readers)With e-book readers, digital books (e-books) can be read. The devices are easy to use, have a large memory capacity and various auxiliary functions such as glare-free displays, zoom functions and, depending on the model, built-in speech output.

Electronic orientation aids (navigation systems): These are devices or apps that detect obstacles and acoustically signal the planned route and geographic location via voice output. Depending on the design, there are navigation systems with ultrasound, laser and the satellite-based Global Positioning System (GPS).

Guide sticksThe cane for the blind (white long cane) supports tactile orientation on paths and in buildings. The tip of the cane senses uneven surfaces and obstacles such as curbs or stairs. In order to use the cane for the blind, mobility training, usually financed by the health insurance, is required.

Task luminaires (low vision luminaires) that are glare-free and flicker-free can improve visual acuity, contrast perception and reading speed, especially during prolonged VDU activity. Standard illuminance levels (expressed in lux) should be at least 50 to 100 percent higher for visually impaired people. When it comes to lighting selection, light colour is a decisive factor, depending on visual impairment. The perception of light colour is influenced by colour temperature, i.e. the lower the colour temperature (measured in Kelvin), the higher the red component in the white colour and the warmer the light is perceived than a white with a higher colour temperature and correspondingly higher blue components. Luminaires with colour temperatures similar to daylight achieve a value of over 6000 Kelvin.

Status: 2019