The Visual Disability Spectrum: The National Eye Institute defines visual impairment as corrected vision of 20/40 or worse. However, students with visual disabilities fall into three different disability categories based on visual acuity, the clinical measure of the eye’s ability to distinguish details (such as a letter or number): Low Vision/ Visually Impaired. Low vision is defined as having corrected visual acuity between 20/70 and 20/160 or having a visual field of 20 degrees or less. Legally Blind. Legal blindness is defined as having corrected visual acuity between 20/100 and 20/200 or having a visual field of 20 degrees or less. Totally Blind. Total blindness is referred to a lack of light perception and the individual’s inability to see anything.
The fact that someone has a learning disability automatically increases his/her chance of experiencing a sight problem. However, there are specific groups of people within the intellectually disabled population who are particularly at risk of developing certain sight problems are but not limited to the following: individuals with Down’s syndrome, Cerebral Palsy, Rubella syndrome, Fragile X syndrome, diabetics and individuals who communicate using behaviors that put their eyes at risk of damage.
In supporting individuals with disabilities and low vision the successful use of low vision aids, emotional and practical support is encouraged. Delay in seeking low vision services can lead to an increased in visual disturbance. The optical magnifier has been the mainstay of visual rehabilitation for many years, but its limits in magnifying power, field of view (FOV), and viewing distance have now been surpassed by electronic magnifiers.2 These are widely available in handheld and desk-mounted formats and often include a zoom function, brightness and contrast controls, and color inversion. They have proven to improve reading ability, often beyond what is a possible using optical magnifier. However, the computerization of magnifiers is only the beginning of harnessing technological advances for the visually impaired.
In conclusion it is important to keep professional and family caregivers knowledgeable and informed to improve the quality of low vision rehabilitation.
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