2. 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)

3. 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)

4. 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)

5. 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)

6. 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.

7. Residual Vision
 Residual vision – the amount and degree of
vision a person has functional use of, despite a
visual disability.

8. 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.

9. 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

10. Visual Acuity
 Visual acuity is how well a person can
see at various distances.

11. Activity 1
 Based on the information received, identify
the different types of visual impairment in
the pictures below.

17. Photo Links
 http://heathersanimations.com/children1.
html
 http://www.kent.gov.uk/adult_social_serv
ices/your_social_services/services_and
_support/sensory_disabilities/deafblind_i
nformation/types_of_visual_impairment.
aspx