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Although
visual impairment and sight loss can affect people in
many different ways, there does seem to be four broad
categories. (please note: the images on this page are
intended to give normally sighted people an idea of
what each of these conditions is like: please move your
mouse pointer over each to see how they change.)
| Central
field loss
Central field loss means the people lose the ability
to see the visual field directly in front of them,
whilst the peripheral area is still visible.
Because
much of the processing associated with discerning
spatial detail occurs in the central field this
impairment can also lead to problems with depth
perception, as well as fine colour discrimination.
As a result reading is almost always affected.
People
with this impairment will still be aware of their
general environment but will have problems with
the fine detail within it. |
Please hold your mouse over the
image to see a simulation of this type of visual
impairment |
| 
Please hold your mouse over the
image to see a simulation of this type of visual
impairment
|
Peripheral
field loss
This is almost the exact opposite of central field
loss: people with this impairment can see straight
ahead, but lose the details of the periphery of
their vision, as if they were looking at the world
through a tube.
This
impairment can influence mobility, as people find
it harder to avoid hazards and obstacles; awareness
of people and things approaching from the side
can also be lost.
Because
of the nature of this impairment, sufferers can
still perform well on traditional visual acuity
and colour vision tests. |
| Combined
central and peripheral field loss
Some medical conditions can lead to people suffering
from both central and peripheral field loss, thus
getting a "worst of both worlds" situation |
Please hold your mouse over
the image to see a simulation of this type of
visual impairment |
| 
Please hold your mouse over
the image to see a simulation of this type of
visual impairment |
Reduced
contrast
This condition results in contrast being lost
and the whole scene becoming washed out. Strong
light sources can wash out the whole environment,
and this condition can be caused by cataracts. |
Return
to the main Signs Now safety and tactile signs page
or also see:
Signs
Now is a leading maker of tactile and braille signs,
and we are here to help throughout the process of specifying
and installing braille, tactile and safety signs. Please
do not hesitate to contact
us for any help you might need in making sure your
workplace complies with the Disability Discrimination
act.
We
have a copy of the Signs
Now tactile and braille signs catalogue available for
free download - and also see our gallery
of photos of safety and tactile signs.
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