There are varying degrees of vision impairments ranging from some usable vision, low vision, to complete blindness. Low vision is defined as a visual acuity between 20/70 and 20/400 with the best possible correction, or a visual field of 20 degrees or less.
There are many possible causes for vision impairment, including damage to the eye, failure of the brain to interpret messages from the eyes correctly, errors of refraction, and eye diseases. Common vision impairments include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, presbyopia, cataracts, glaucoma, macular degeneration, retinitis pigmentosa, retinopathy, and monocular vision.
Visual impairments often make life activities more difficult when environments are designed with an assumption of average sightedness.
Observing Visual Impairment in the Classroom
Faculty might observe the following characteristics in students with impaired vision:
- May have great difficulty or an inability to see visual information from a distance
- May request that someone read to them from the board
- May request that handouts, etc. be enlarged
- May request a seat in the front of the room
- May request that a large font be used for projected slides
Related Functional Characteristics
Contrast Vision Deficiency : Students with certain visual impairments may have difficulty discriminating between different levels of intensity of colors, shades of gray, or light levels.
Fatigue (Cognitive) : Students with visual impairments experience cognitive fatigue because they have to concentrate and process information more slowly.
Flicker or Pattern Sensitivity : Flickering can cause pain or exacerbate vision problems for students with certain visual impairments.
Glare Sensitivity : Light from a direct overhead light fixture, sunlight, or other sources of direct light can cause reflections making seeing especially difficult or even cause physical discomfort or pain.
Information Processing Speed : Visual impairments impact the speed and accuracy of visual processing, impacting the speed of information processing.
Low Vision : Low vision becomes a difficulty when it is uncorrectable.
Processing Deficit (Visual) : The ability to process visual information can be impacted negatively depending on the type of visual impairment.
Service Animal Needs : A service animal may be used by students with severe visual limitation to assist them in travelling.
Visual Field Function : Certain visual impairments can cause a student's field of vision to become narrowed making it difficult for the student to see or detect movement or objects that are not directly ahead.
Visual Tracking Problem : Difficulties with visual tracking can occur as a result of various visual impairments.
The Building Accepting Campus Communities (BACC) project was funded by the US Department of Education Office of Secondary Education grant #P333A080070-09. The University of Nebraska does not discriminate based on gender, age, disability, race, color, religion, marital status, veteran's status, national or ethnic origin, or sexual orientation.