1. Visual Impairment Definition According to the US Department of Education (2006), Visual Impairment including blindness means an impairment in vision that, even with correction, adversely affects a child’s educational performance. The term includes both partial sight and blindness.(p.1265)
2. Blindness Definition A person, who is blind according to the Centers for Disease Control (2005), has a visual acuity worse than 20/400, with the best possible correction, or visual field of 10 degrees or less. (p.1)
3. Low Vision Definition Corn (1989) stated that low vision is a level of vision, with standard correction hinders an individual in planning and/ or execution of a task, but which permits enhancement of the functional vision through the use of optical or nonoptical devices, environmental modifications and /or techniques. (p.28)
4. Legally Blind Definition The American Foundation for the Blind stated that legally blind is when the central visual acuity of 20/200 or less in the better eye, with best correction, or a diameter of normal field that does not subtend or angle greater than 20 degrees at its widest point. (p.1)
5. Visual Efficiency Definition Visual efficiency- This is how well people can use their sight. It is influenced by many factors, including the person’s acuity and peripheral vision, environmental conditions and psychological variables.
6. Residual Vision Residual vision – the amount and degree of vision a person has functional use of, despite a visual disability.
7. Peripheral Vision Peripheral vision is the width of a person’s field of vision, or the ability to perceive objects outside of the direct line of vision. This aspect of vision helps people to move freely through their environment. It helps them to see large objects and movement. Severe limitations in peripheral vision is sometimes called tunnel vision or restricted central vision.
8. Categories of Visual Impairment Normal acuity Impaired acuity Normal vision field Impaired peripheral fields Impaired lower visual field “Blind spots” in the visual field Blind
9. Visual Acuity Visual acuity is how well a person can see at various distances.
10. Activity 1 Based on the information received, identify the different types of visual impairment in the pictures below.