What is Visual Impairment?
Visual impairment is an umbrella term that accommodates all types and degrees of visual loss or deviation. A child who has low vision or partial sightedness: Myopia (Short sightedness), hyperopia (Long sightedness) astigmatism (blurred vision) or no light perception (total blindness) or has restricted central vision or has lost sight in one eye is considered a child with visual impairment. These instances typify some form of loss or deviation or damage of the visual apparatus and therefore are regarded as visual impairment.
In this context, visual impairment is referred to both blindness and low vision. Visual impairment can be defined legally and educationally. This context adopts the educational definition of visual impairment which considers the ability or degree of a child to use visual ability educationally. Educationally, a child with low vision is the one who has some residual vision, and therefore can read enlarged prints. On the other side, an educationally blind child is the one with very limited vision and thus relies on reading and writing by using the braille system or by using audio-tapes.
Visual impairment can be defined legally and educationally. Legal definition describes visual impairment by considering the visual acuity of a child. It describes a blind child as the one having visual acuity of 20/200 or less than that, even by using optical devices. This means that, a child with blindness can see an object at 20 feet whereas a sighted child can see at 200 feet. A legal definition considers a child with low vision as having visual acuity of 20/70 meaning that, a child with low vision can see an object at 20 feet whereas a child with normal vision can see at 70 feet. In this context, educational definition is relevant because it shows directly the impacts of visual impairment on the learning process of a child. Visual impairment can be congenital or adventitious. A congenital visual impairment can occur before or at birth. Congenital visual impairment is caused by a number of factors such as genetic traits, infections (like German Measles) which is transmitted from mother to the developing fetus, self-medication or taking unprescribed drugs by a pregnant woman and long labor, etc. While, adventitious visual impairment occurs sometime after birth or later in life. Some of the adventitious causes of visual impairment include conditions like diabetic retinopathy, glaucoma, cataract, trachoma, muscular degeneration, childhood diseases, bacterial infections, trauma or accidents, poor nutrition.
Before imposing any teaching to children with visual impairments, it is very important that a teacher knows how the loss in vision influences the learning process. Visual information is crucial in helping children observe and interpret what happens in the environment. It is also an important prerequisite for conceptual development of a child's learning. Malformation and destruction of this part of the body, brings about a reduced amount of sensory data to the learner, leading to deficit or delay in various skills learned through watching and imitation from others. This impacts language development, reasoning skills, problem solving abilities and abstract thinking. This finally caused a great impact on the child’s learning and performance, because a child cannot observe and use visual information to interpret various learning situations happening in the environment. If visual impairment occurs during early childhood, cognitive and language development is impaired. But if the loss of vision is after five years, below which visual memories cannot be retained, then there will be some visual memories. This visual memory will be very helpful in the learning process through construction and formation of images, and concepts later by relating the new concept and experience acquired earlier in life.
There are basically three ways through which children with visual impairment can get information from the environment. Verbal description is the most important source of information to children with visual impairment. However, verbal descriptions provided by others are always incomplete and cannot satisfy the child’s needs. Another way is the use of tactile stimuli. However, a tactile method is also not effective, because a child needs to feel an object repeatedly in order to grasp the image of the object. Finally, children with visual impairment rely on self-exploration about the world. This way is limited in amounts of information that can be accessible to children with visual impairment. All in all, these modalities together cannot effectively compensate the visual stimuli, they are there just to reduce the impacts to learning caused by lack of vision. Therefore a teacher teaching children with visual impairment in inclusive classrooms needs to plan teaching based on these assumptions.
Total Blindness
Total blindness is the inability to discriminate light from dark, or the total inability to see. Total blindness is otherwise known as legal blindness, and has visual acuity of 20/200 or less in the better eye after the best possible correction with glasses.
Low Vision
Low vision is a severe visual impairment with minimal visual function after correction. It can be increased through the use of optical aids and environmental modifications (Corn & Ryser, 1989). Children with low vision learn from vision and other senses. Functional vision will depend on factors such as lighting, size of print or objects, and distance. Low vision is characterized by visual acuity of 20/200 to 70/200 (Snellen) or 6/18 to 6/60 in the better eye after the best possible correction or a field of vision between 20 to 30 degrees.
Partially sightedness
Children with partial sightedness would be able to use the sight to move about, but may not be able to use it for academic task. The category is based on the simultaneous consideration of the three aspects of vision namely; visual acuity, field of vision and visual functioning. In a broad sense, visual defects into loss of clear vision, central vision or peripheral vision. All these loose are considered by measuring visual acuity, field of vision and level of visual functioning:
A- Visual acuity refers to the ability of the eye to see details. The visual acuity for distance is measured as the maximum distance at which a person can see a certain object, divided by the maximum distance at which a person with normal eyesight can see the same object. Thus a visual acuity of 6/60 means that the person examined can see, at a distance of 6 meters, the object which a person with normal eyesight would be able to see at 60 meters. If vision is so impaired that to see the biggest E of the E-chart, the person has to come within 6 meters or even nearer, he is considered blind. The simplest method of testing visual acuity is to see whether the person can count fingers at a distance of six meters (6 Mts).
B- Field of vision refers to the extent which both eyes can easily see in front. The normal field of vision is 180 degrees in front of the eye. It is determined by the Confrontation Test in which mapping is done on a chart having concentric circles marked upon it. The simplest method of testing is to bring a snapping finger from the side of the ear to the front, move it up and down, and mark the position where the person can see the finger.
C- Visual functioning relates to the condition of the eye. It is determined by the experience, motivation, needs and expectation of each individual in relation to whatever visual capacity is available to satisfy curiosity and accomplishment of activities for personal satisfaction. The visual functioning refers to the degree to which/ability of a person to use vision for all daily activities.
What Are Assistive Technologies for Children and Adults with Visual Impairment?
Assistive Technology refers to any item, piece of equipment, or product system, whether acquired commercially off the shelf, modified or customized, that is used to increase, maintain or improve functional capabilities of a child and adult with visual impairment. The Assistive Technology devices can be Hardware or Software.
Hardware Devices
Talking calculator: it is a handheld device battery powered calculator that talks when being operated. It can add, multiply, subtract and divide numbers. Every key pressed by the operator will be converted into a clear human voice. It is used by students with visual impairment students with visual impairment. Hence, see the picture of talking calculator below:
Digital voice recorder: it is a manual device that records, stores and converts sound, such as speech and other sounds into a digital file that can be used, moved from one electronic device to another, played back by a computer, tablet or Smartphone and stored like any other digital file. It is used by students with visual impairment to record their lectures and other information in the class. Hence, see the picture of digital voice recorder below:
Portable Talking Dictionary: it is a manual device that provides spoken pronunciations of words in addition to the normal information provided by a dictionary. In some cases, such a dictionary also speaks the definition, synonyms and other information. It is used by students with visual impairment. Hence, see the picture of talking dictionary below:
Perkins Brailler: it is a manual Brailling device. It is sometimes calls classic writing machine used to create Braille documents even if there is no electricity available. It is available for students with visual impairment in schools. Hence, see the picture of perkins Brailler below:
Electric Perkins Brailler: it is an electric Braille writing device. It can only be used when it is plugged into electricity. It enables Braille writing with much less force and for longer periods of time than manual machines. It is designed for students with blindness and those with low vision. Just like a standard Perkins Brailler, it is a portable machine. Hence, see the picture of electric perkins Brailler below:
Smart electronic Perkins Brailler: it is an electronic Braille writing device which combines a standard Braille keyboard, speech output, and Simbraille and large print on a colorful screen, creating and producing Braille documents. It can be used when it is plugged into electricity and the battery is charging or after the battery has been charged and plugged out. It is used by both students with blindness and lone vision. Hence, see the picture of smart perkins Brailler below:
Braille keyboard: it is a specialist import device that allows students with visual impairment to type and enter text or instructions for the computer in Braille. It enables students with visual impairment to do common tasks such as writing, browsing the internet, typing in Braille and printing in text, engaging in mail and reading documents. A Braille keyboard is connected to a computer: laptop or desktop. Hence, see the braille keyboard below:
Braille Embosser: it is a device that is connected to a computer both laptops and desktop, Braille note takers, mobile devices or flash drives to generate, render and produce text or printed material into a Braille writing system. Braille Embosser is also known as Braille printer. To produce hardcopy Braille, the Braille printer has to be connected to a computer and Braille translation software must be installed to translate text into Braille code, which is then typically printed out in a Braille writing system. Braille embossers can emboss single–sided or double-sided (called interpret). Hence, see the picture of braille embosser below:
Braille Note Takers: they are small and portable devices that may be used by a student with visual impairment to take notes in class using either (featuring six large keys that correspond to the 6 dots in the Braille cell), standard (QWERTY) keyboard, or both although each devices officers different features, many can be used by students with visual impairment to read books, write class assignment, find directions, record lectures and listen to podcasts. Information can be readily transcribed in order to provide the students with visual impairment a means to communicate with peers, teachers and others who do not read Braille. The note-taking devices generally are the size of a book and are tastily carried and used by the students with visual impairment. Braille note taker is also known as Braille sense. Hence, see the picture of braille note taker below:
Digital Talking Books (Hardware): These are not really things that you can hold, although they usually come on a CD-ROM today. Rather, they are files, which may also be available on the web. To put it technically, digital Talking Books are well-organized collections of computer files produced according to specifications that are published in the standards that define them. They are a medium-independent information access-and-delivery technology—the files can be stored on CD, in a directory, or on a memory card—that is based on open standards, primarily the World Wide Web Consortium’s (W3C) XML (Extensible Markup Language) and SMIL (Synchronized Multimedia Integration Language), pronounced smile.
Magnification Devices: these are devices that increase or enlarge the size of text for students with residual vision or low vision. There are memories, magnifier devices available, ranging from simple hand-held magnifying glasses to video magnifiers ( such as CCTVS) and screen magnifiers for use with a computer. Hence, see the picture of magnifier devices below:
Color Identifier Device: This is a talking color detector device which can differentiate a variety of colors with a voice once it touches on the surface. Hence, see the picture below:
Money Identifier Device: This is a talking money Identifier that helps visually impaired individuals to identify money with a voice function. Other tactile note identifiers are money organizer wallet, notex, NoteChecker etc. Hence, see the picture below:
Talking Watch: Talking watch offers a sense of hearing to a person with visual impairment. At the touch of a button, the person can instantly have the time spoken to him/her. The talking wrist watches are available to blind children and adults. Talking watches are durable and reliable watches feature true quartz accuracy and include a host of features such as multiple alarm sounds. Hence, see the picture of talking watches below:
Software Devices
Window Eye Software (screen reader): This is software that the computer screen reads out loud. This allows students with visual impairment to hear what is happening on their computer, or read it through special refreshable Braille displays. This allows students with visual impairment to use standard windows software, like microsoft office, internet explorer, email programmes, and so on.
Duxbury Braille Software: This software is a Braille translator. Translation between print and Braille is its primary function. It can translate into grade 1 (unconstructed) or grade 2 (contracted) literary Braille for many languages, and also into several different Braille codes for mathematics and other technical notation. It can also translate from Braille into the equivalent print for several language and Braille codes.
Talkback Braille Keyboard: This is a software keyboard for android which enables a student with visual impairment to position their fingers on the screen and type as if they were using a Perkins Brailler. It is a new virtual Braille keyboard integrated directly into android. It is a fast and convenient way for students with visual impairment to type on their smart phones without any additional hardware.
Text-to Speech software: This is a type of ICT software device that reads aloud digital text- the words on computers, smart phones and tablets. All kinds of text files can be read aloud, including word and page documents. Even online web pages can be read aloud.
Digital Accessible Information System (DAISY): it is a technical standard for digital audiobooks, periodicals, and computerized text. DAISY is designed to be a complete audio substitute for print material and is specifically designed for use by persons with "print use limitation", including children blindness, low vision, and partial sightedness. Based on the MP3 and XML formats, the DAISY format has advanced features in addition to those of a traditional audio book. Users can search, place bookmarks, precisely navigate line by line, and regulate the speaking speed without distortion. DAISY also provides aurally accessible tables, references, and additional information. As a result, DAISY allows visually impaired listeners to navigate something as complex as an encyclopedia or textbook, otherwise impossible using conventional audio recordings.
DAISY multimedia can be a book, magazine, newspaper, journal, computerized text, or a synchronized presentation of text and audio. It provides up to six embedded "navigation levels" for content, including embedded objects such as images, graphics, and MathML. In the DAISY standard, navigation is enabled within a sequential and hierarchical structure consisting of (marked-up) text synchronized with audio.
Digital Talking Book players (Software)/ Downloadable Audio Books: These books are digital files that contain the same content as conventional audio books but can be downloaded onto a personal computer or a portable device such as an MP3 player. Apps for the iPhone, iPad or iPod Touch make the download and listening process seamless for many audio books. If you are not technically oriented, the digital option may seem unfamiliar, but it does have advantages that make it worth exploring. The main advantage is navigation. CDs offer limited movement backward or forward within the text. Digital playback is much more flexible, allowing the user to jump back or forward by chapter or sometimes by page. You can even set digital bookmarks that let you find a particular passage instantly. Here is more information about downloadable audio books:
Electronic Audio Books are recorded electronically and stored in files on the Web, or downloaded to your own computer.
Sometimes they are especially designed for people who are blind or have low vision and use the DAISY (Digital Accessible Information System) format.
This format has encoded markers for chapters, subheadings, paragraphs, and other codes that help the listener navigate through the book and bookmark passages of interest.
The DAISY format means that Digital Audio Books will not work on players that are not designed to play them.
If you have a computer, you can get software that can play the DAISY format. You can also buy a stand-alone machine that plays Digital Audio Books.
Some Personal Digital Assistants (PDAs) can play the DAISY format. Look for a PDA that understands DAISY and has sufficient memory for storing your books.
Stand-alone machines can also be small and portable and will play MP3 files and music CDs too.
DAISY books can contain both text and audio files. The text portion can be displayed on a braille display or on a screen in a larger font size. You can search the text for key words or passages. Unlike CDs, you don’t have to rewind or fast forward. And you can increase or decrease the reading speed without affecting the quality of the narrator’s voice. Ask yourself the following questions before purchasing a digital audio book player.
Do you want a portable player or a software player that runs on your computer? If you want to use it on your computer, you will need a software player that is compatible with your computer’s operating system.
If you have a portable player, does your PDA already support the DAISY format and have sufficient memory for storing books? Can your PDA memory be expanded?
Do you want a player that plays CDs, or a player that plays files transferred directly from your computer? Should it also play MP3, WAV, WMA file formats?
If you are buying software, do you want a version that allows you to produce, as well as listen to, books?
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