Blindness and Low Vision

What is meant by legally blind?
Person whose visual acuity is 20/200 or less in the better eye after best glasses or contacts.
The legal definition of blindness is based on what?
Visual acuity and field of vision.
What is visual acuity?
the ability to clearly distinguish forms or discriminate among details
What is meant by “20/20 vision”?
Does not mean perfect vision. It means that at a distance of 20 feet, the eye can see what a normal eye sees at that distance.
What is increasing as the bottom number increases in 20/20 vision?
Visual acuity decreases.
What does it mean if Jane has 20/200 vision while wearing glasses, and is she legally blind?
She must be at a distance of 20 feet to see what normal sighted people sees at 200 feet. She is legally blind.
What is the IDEA definition of visual impairment?
Includes blindness (full and partial). Means an impairment in vision that, even with correction, adversely affects a child’s educational performance.
What is “totally blind”?
Receives no useful information through vision and must rely on other senses for all learning
What is “functionally blind”?
Has so little vision that learning is primarily through the auditory and tactile senses. May be able to supplement learning and certain tasks with limited vision.
What are some causes of visual impairments?
Refractive Errors (nearsighted/farsighted), structural impairments (glaucoma/cataracts), and cortical (damage to part of brain).
What is braille?
Primary means of literacy for the blind. A tactile system of reading and writing in which letters, words, numbers, and other systems are made from arrangements of raised dots.
When are children usually introduced to braille?
First grade
What is “functional vision”?
Denotes how well a person uses whatever vision he has. Is not determined by measurements of visual acuity or field of vision.
What are Optical Devices?
Devices that help people with low vision perform better at certain tasks. Does not give normal vision, just improvement.
Give examples of some optical devices
glasses, contact lens, small handheld telescopes, and magnifiers placed on top of printed pages.
Are optical aids usually all-purpose or specialized?
What are the three basic approaches used by low vision students to read print?
approach magnification, lenses, and large print
What is approach magnification?
Reducing the distance between the eye and the page of print.
What are some ways a teacher can accommodate the slower reading rates of children with low vision?
provide up to 2 times as much time for reading, ensure sufficient time for study, use auditory reading aids if time is not available, and allow extra time on tests.
What is the most effective low-vision adaptation for the classroom?
Proper lighting, which may include an adjustable lamp. Lighting should come from the side of the eye with the greatest usable vision.
What is Orientation and Mobility instruction?
Curriculum that teaches students with visual impairments to understand their environment and maneuver through it safely and effectively.
What is “Orientation”?
Knowing where you are, where you are going, and how to get there by interpreting information from the enviornment.
What is Mobility?
moving safely and efficiently from one point to another.
Are Orientation and Mobility the same thing?
No. They are complimentary.
What aids are included in Orientation and Mobility?
Cane skills, guide dogs, sighted-guides, and electronic travel aids.
What is taught in a Listening Skills curriculum?
Proper instruction and experiences that teach how to use hearing more efficiently
What is a Functional Life Skills curriculum?
Daily and career skills such as cooking, personal hygiene, shopping, transportation, etc.
What percentage of visually impaired children are educated in public schools?
What is the Itinerant Teacher Model?
Sometimes called vision specialists. They are specially trained teachers that collaborate with gen. ed. teacher, provide direct instruction, obtain or prepare specialized material, and consult with parents.