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Assistive products for people with blindness and visual impairments

Operating computers, using the internet, reading content and finding your way around are key prerequisites for being able to inform yourself, communicate and be 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, examples of assistive product types are described here with a focus on computer hardware and software as well as electronic assistive products.

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

  • large numbers or letters
  • large, illuminated displays
  • Voice input and voice output
  • Tactile marking points (Braille)
  • Guide lines and edges
  • Two-sense principle of accessibility (acoustic and vibrating/tactile alarm signals)
  • Ultrasound or GPS (Global Positioning System) for orientation
  • RFID technology (Radio Frequency Identification) for labeling or product recognition

Braille printer (Braille printer)Braille printers punch Braille or graphics onto special paper. The braille paper is considerably thicker and more robust than conventional paper for standard printers. This makes information tangible and therefore legible for people with blindness who can read Braille. Special conversion software converts files into the Braille character set. There are double-sided Braille printers with continuous paper or small, handy Braille printers with a single-sheet feeder for mobile use.

Braille displaysBraille displays : Braille displays the screen content in Braille, which can be felt with the fingertips using 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. In most cases, a combined voice output on the computer is also used. With a Braille display, you 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 working, for example with a notebook.

  • Braille notation devicesBraille notation devices 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, speech readers)Reading systems scan paper documents such as books, articles or invoices and save them in a file. 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 voice output. Optionally, people can also read the text using 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 compact devices that contain all components from scanner and text recognition software to voice output. The functions are distributed across a small number of easily tactile control elements and are therefore easy to operate. Output is via voice output or Braille display. Some closed devices save the scanned texts. Closed reading systems are particularly suitable for people with late-onset blindness and replace the use of a computer.
  • Open reading systems are usually used at 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 via voice output. The data can be saved and processed using conventional word processing programs. The system can be controlled via the computer keyboard.

Large character keyboardsThese keyboards for people with visual impairments have high-contrast and larger lettering as well as tactile markings in some cases.

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

Screen readerThe screen reader is a complex screen input and readout software that controls screen content. The software interprets the screen information (e.g. text, 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 that is installed on the PC (e.g. JAWS) as well as integrated screen readers. TalkBack, for example, is Google's screen reader on Android devices, while VoiceOver is built into iOS devices. Screen readers also help users to use large parts 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 content larger, but also enhances contrasts and colors and tracks the focus (e.g. scrolling text, document reading function). Various output media (e.g. voice output, Braille display) can be combined with the software. The information that is not visible in the enlarged image section is thus available, which is easier on the eyes.

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

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 then be edited or copied. The text files are usually output in combination with computers and mobile devices via screen reader software (e.g. voice output). Scanners (e.g. flatbed scanners) usually 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 stored descriptions. This allows products and sometimes faces to be recognized, for example.

Speech 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. Depending on the degree of visual impairment, however, speech recognition is only useful in conjunction with other assistive products such as Braille displays, screen readers, magnification systems or speech output. Mobile devices with the Android and iOS operating systems have their own integrated speech recognition.

AppsThere are numerous, often pre-installed apps (applications for small displays and touchscreens) for mobile devices such as smartphones or tablets, which are also helpful for people with visual impairments and blindness. Examples include apps for recognizing text, barcodes, colors, light or banknotes. Native apps are tailored to the respective operating system of the computer (e.g. iOS, Android). Web apps run platform-independently in the respective internet browser and should provide good support for the other assistive products required (e.g. screen readers). You can search for other 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 using the keyboard via direct input commands and menus. The range of software includes accessible currency converters, email clients, accessible database software or management programs for electronic files and other document management systems.

Magnifying visual aids support people with visual impairments in reading and spatial orientation when glasses or contact lenses are not satisfactory. With increasing magnification, however, the image section displayed becomes smaller.

Visualaids: Optical low vision aids magnify information on paper or displays at close and long range 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 design, a magnification of up to 12x is possible.

  • Optical aids for close-up visionThese include magnifiers, magnifying spectacles and lenses. There are, for example, magnifiers and stand magnifiers with lighting or large screen magnifiers that are placed in front of a TV screen. VDU glasses for the workplace are adapted visual aids for computer activities when normal reading glasses, varifocals or contact lenses do not meet the visual requirements. The distance to the monitor is adjusted to around 50 to 70 cm for screen glasses. Employers often cover the full cost of the screen glasses as part of their occupational health and safety obligations.
  • Optical aids for distance visionThese are, for example, binoculars, telescopes and telescopic glasses. Telescopic glasses or monoculars (pocket telescopes) make it easier to find your way around in unfamiliar surroundings (e.g. reading road signs or display boards from a greater distance). Telescopic magnifying spectacles (telescopic spectacles with clip-on magnifier) can make reading easier.

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

  • Screen readersElectronic screen readers, also known as camera reading systems, record text excerpts (e.g. documents, books) and transfer them to a screen at a high magnification. They can also be useful if there is an increased need for contrast. Screen readers are available for near and/or far range (with remote camera), for example for recognizing the content of PowerPoint presentations or on school blackboards. A distinction is made between stationary, portable and mobile, small screen readers.
  • Electronic magnifiersElectronic magnifiers are pocket-sized, battery-operated screen readers for mobile use. They magnify much more than optical hand-held magnifiers.

Cordless landline telephones and cell phones (cell phones): Landline and cell phones adapted to the sensory impairment have, for example, tactile large keys, high-contrast displays, memory functions for direct dialing, 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.

SmartphonesSmartphones are like small computers that can be used to make phone calls. They offer a wide range of pre-installed or optional operating aids such as zoom function, screen reader, voice output or text recognition. You can find out more about the accessibility of cell phones and smartphones here.

Audio players (DAISY player)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 adaptations so that you can turn pages, skip 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)E-book readers allow digital books (e-books) to be read. The devices are easy to use, have a large storage capacity and various auxiliary functions such as anti-glare displays, zoom functions and, depending on the model, built-in voice output.

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

Canes for the blindThe 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 kerbs or stairs. In order to use the cane, mobility training, usually financed by health insurance, is required.

Task lights (low vision lights) that are glare- and flicker-free can improve visual acuity, contrast perception and reading speed, especially during long periods of screen work. The standard illuminance levels (expressed in lux) should be at least 50 to 100 percent higher for visually impaired people. Depending on the visual impairment, the light color is decisive when selecting light. The perception of the light color is influenced by the color temperature, i.e. the lower the color temperature (measured in Kelvin), the higher the red component in the white color and the warmer the light is perceived than a white with a higher color temperature and correspondingly higher blue components. Lights with color temperatures similar to daylight reach a value of over 6000 Kelvin.

Status: 2019