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By Linda s. Petty, O.T.Reg.(ON)
Clinical Specialist
Adaptive Technology Resource Centre (ATRC)
University of Toronto

Presented at the 19th annual Closing the Gap conference, Minneapolis Minn. Oct. 18, 2001


Muscle-tone abnormalities such as high or low tone or pathological reflexes affect the control of eye musculature and functional vision. This paper discusses the impact of neurological impairments on ocular motor control and provides positioning recommendations to enhance functional control of vision. The implications of tactile dysfunction for visual accommodation are explored, as traditional educational tools for the visually impaired rely heavily on tactile sensory skills. Accommodation strategies of e-text, scanning and optical character recognition (OCR) software with computer input modifications are highlighted as essential high technology adaptations.


Literature from both eye care specialists and rehabilitation sources support The existence of concurrent visual and physical disabilities, although the wide variance in statistics are a cause for concern regarding the accuracy of diagnostic services for this group. The following is gathered from a range of relevant literature:

  • 75 - 90% of children with severe impairments have a visual impairment
  • High Risk populations for visual impairment include: Cerebral Palsy, Premature births, Down¹s Syndrome, Hearing Impaired, Fetal Alcohol Syndrome Beukelman & Mirenda, 1992; Erhardt, 1990; Mirenda & Mathy-Laikko, 1989
  • Impairments include: visual acuity loss, eye muscle imbalances, visual field Deficits, visual perceptual skill delays and processing problems

Incidence of vision problems: normal population

    Refractive error: 15-30%,
    Strabismus: 2 - 4%
    total: 30-35%

Compared to vision problems associated with congenital conditions...

Incidence of vision problems: Cerebral Palsy

    refractive error: 21-76%,
    Strabismus: 15 - 60%
    Other problems: 1 - 25%
    Total: 50 - 78%

Incidence of vision problems: developmental delay

    Refractive error: 52%,
    Strabismus: 16 - 40%
    Other problems: 21%
    Total: 50 - 80%

Incidence of vision problems: down’s syndrome

    Refractive error: 42-73%,
    Strabismus: 30 - 57%
    Other problems: 0%
    Total: 60 - 85%

Unfortunately, treatment for the physically disabled groups focus mainly on motor impairments- visual problems are often undiagnosed, not treated or poorly understood, especially in clients with motor-speech or literacy impairments. The following strategies are offered as having potential to address both problems in this population.

Adaptation Strategy #1: Modify positioning for student and equipment to enhance visualization

See Identifying and Adapting for Visual Impairment in the Client with Physical Disabilities , already web published on ATRC site 

Adaptation strategy #2: Tactile Skill Assessment

Another significant, but rarely assessed sensory area is tactile skills
Severe CNS damage usually results in severe damage to tactile system
Little studied, however responses are often abnormal i.e. tactile defensive
Numerous acquired disabilities also affect tactile abilities: Multiple Sclerosis, Diabetes Mellitus
Do not presume client’s ability to use tactile skills without testing

Recommend completing the pre-braille skills test from the texas institute for the blind and visually impaired, found in the technology section at:

Adaptation Strategy #3: Use Adapted input, computerized aids for visual impairments which cannot be accommodated for with positioning

This is a difficult to fit population technically, as computer access methods for physical disabilities rely heavily on vision. High tech aids for visual disabilities rely on multiple keystrokes from whole keyboard, especially the numeric keypad, and are memory intensive. There is frequently a conflict between timing and representation of alternative input device and vision aid, preventing the use of alternative input devices such as scanning.

The process to accommodate both areas of need with high tech devices should include:

  1. Thorough identification of needs and problems- physical and visual- in personal, productivity and leisure reading and writing
  2. Quantitative computer access evaluation to establish optimal computer access method
  3. Application of computer access to control of visual access software, computer system and application software

The Computer as a Reading Aid

Many children with muscle tone abnormality have access to a computer for writing, without needed modifications to make the system support reading needs. Many of the same group cannot independently use standard textbooks, reference material and are not always accommodated with enlarged print material or taped material at school.

Pilot Study Results

A study on Optical Character Recognition (OCR) used by children with physical disabilities was done with an OT research student at the ATRC in the spring 2001 to examine the levels of familiarity with and use of OCR by teachers and educational assistants of children with physical disabilities. The study surveyed a segregated specialty grade school for children with physical disabilities- respondents all had training in special education. One hundred percent of the respondents were not familiar with OCR, even though most of their students had difficulty handling paper books and many had multiple impairments, including visual impairments. These results suggest the use of a computer and OCR technology, as a reading aid, is being under-utilized in education for children with physical disabilities. The following options are available to apply this technology in the classroom or home environments.

Minimum cost High Tech Reading Supports

  • Scanner with at least 1200 by 1200 dots per inch resolution- cost can be as low as $150.00
  • Mainstream optical character recognition software - omni pro 11 for $500 USD or $150 if upgrading from a "lite" OCR package or Textbridge Pro for $150 —

The material can then be scanned in using the OCR software. The software can retain graphics, columns, etc. Files are then opened in a word processor and read with text to speech program- see the Technical Glossary For a listing of programs- or with the doc reader of zoomtext extra level 2 (

Other options for low cost text to speech programs:

Higher cost aids offering more extensive features and greater independence

  • OCR/reading software aimed at the low vision/blind user, providing high contrast, magnified text with highlighted tracking and viewing of original graphics- Kurzweil 1000 ( or Openbook (
  • OCR/reading software aimed at the learning disabled population: Kurzweil 3000 ( or Wynn ( mouse oriented with numerous study skills features.
  • Wordsmith, for scanning and reading within msword or ms internet explorer:
  • Zoomtext extra level 2 provides screen magnification with speech- can use Document reader in ticker format, or use speak it tool in columns.

Alternative Access to OCR/Reading Software

  • Programs for visually impaired clients have keystroke equivalents, however, these may be complex and not able to be accessed sequentially using sticky keys. Some programs, such as Zoomtext Extra Level 2, allow re-programming of hot keys.
  • Programs for learning disabled clients are generally visually based and require good mouse control and visual scanning skills for efficient access.

Other Input Options

  • Kurzweil 1000 has an external keypad, labelled with it’s scanning and reading functions for easy use with one finger or limited reach.
  • Openbook no longer supplies an external keypad, however, this could be purchased separately.
  • Major commands for either program can be mapped into Intellikeys overlays
  • Can use any direct input of alternative keyboard, mousekeys, or programmable keyboard.
  • Using scan lines is problematic- does not input keystrokes at the level looked for by the OCR program, however, talking books can be created with Clicker4, at
  • Can input using morse code to control any software and the operating system, but only with a hardware input device, such as Darci USB ( or Bloorview Minimorse.
  • Voice recognition would work using menu commands, if the user could see adequately, or use screen magnification in conjunction with OCR.

Utility and importance of Electronic Text

Electronic text is an important substitution for physically managing paper and books, travel to libraries, etc. On-screen reading can be magnified, displayed in different fonts, foreground/background colours, highlighted to support tracking. Pages are turned automatically; locations can be book marked, facilitating independence and control of the material. Images can be viewed with magnification, in colour or higher contrast black and white, mimicking a CCTV. Text material can be cut and pasted for writing tasks and copy typing minimized or eliminated.

Configurations with CCTVs

CCTV cameras can display a magnified image on a computer monitor to minimize footprint of equipment. This allows client to view images or additional material along with electronic text in their word processor, either with a split screen or by toggling between the two. The split screen option offers horizontal or vertical splits, or full screen of computer or CCTV; this is available with many CCTVs. While controls can be difficult for manual adjustment with motor impairment, an auto focus is available in Pulsedata’s Smartview2. Optimally, children with low vision would have use of both a CCTV and a scanner with OCR software for reading and writing support.

Web Resources

Programs working on access to technology for visual and physical impairments

Sources of Electronic Text