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Learners with Blindness or Low Vision. By: Stephanie Griffith and Leah Helmer. Definition.
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Learners with Blindness or Low Vision By: Stephanie Griffith and Leah Helmer
Definition • Legally Blind: have visual acuity of 20/200 or less in the better eye even with correction (e.g., eyeglasses) or has a field of vision so narrow that its widest diameter subtends an angular distance no greater than 20 degrees. • Low vision (partially sighted): have visual acuity falling between 20/70 and 20/200 in the better eye with correction.
Prevalence • Blindness is primarily an adult disability • Approximately 1/10 as prevalent in school-age children as in adults • Federal government classifies only about 0.05% of the population ranging from 6-7 years of age as “visually impaired.” This includes those who are blind or who have low vision. • One of the least prevalent disabilities in children
Anatomy and Physiology of the Eye • The light rays have to do the following: • Pass through the cornea, which bends the light rays so that image will be focused • Pass through the aqueous humor • Pass through the pupil • Pass through the lens, refining and changing the focus of the light rays before they pass through the vitreous humor • Come to a focus on the retina containing nerve fibers connected to the optic nerve, carrying the information back to the brain.
Identification of Visual Impairment • Snellen Chart • Functional Vision Assessment • Teacher observing student in daily activities • Take note of how the student functions under certain conditions (sunny or cloudy weather) • Variety of tasks (reading books, navigation within the classroom or from class to class, etc)
Causes • Refraction errors (most common) • Myopia: nearsightedness • Hyperopia: farsightedness • Astigmatism: blurred vision • Some conditions that affect primarily children • Retinitis pigmentosa: causes tunnel vision and night blindness • Cortical visual impairment results from brain damage or dysfunction • Retinopathy of prematurity can be caused by excessive concentrations of oxygen or other factors
Educational Considerations • Braille • Use of remaining sight • Large print books, magnifying devices can be used for close or distance vision • Orientation and Mobility Training • Canes • Guide dogs • More practical for adults • Alert owner of dangerous areas
Assessment of Progress • Teachers can monitor progress in Braille skills involved in reading and math using curriculum-based measurement • Professionals can assess academic outcomes using braille versions of standardized tests • Testing accommodations often include testing in braille, large-print, or extended time
ACTIVITY TIME! • The next slide shows the Braille Alphabet. • Write your first and last name in Braille, as well as your home address. • This will simulate how a child with blindness reads!