Download Lighting Information for Individuals with Cortical Vision Impairments

Lighting for
Children with
Immature
Visual
Systems and
those with
Cortical/
Cerebral
Visual
Impairment
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When it comes to learners who are
very young or who have CVI, and how
they are affected by light, we don’t
know much. But here is what we do
know.
We know some learners who have
CVI, brain injury or are very
young,
• Experience light in ways different
from adults with typical vision
• Experience light in ways different
from learners their same age
• Experience light in ways different
from youth and adults with the same
vision diagnosis
• Sometimes experience light in a
synesthetic way.
• Experience confusion and avoidance
in the presence of blue light
• Experience confusion and avoidance
in the presence of very bright light
What are some of
the ways this is
manifest?
• Adult turns away from light
• Adult shows signs of stress (squint, yawn,
close eyes, rapid blink, complain)
• Adult becomes non-responsive
• Adult heart rate speeds up
• Adult returns to his/her normal
responsiveness when the offending light
source is removed
Research has shown:
• Studies that involved children with
cortical dysfunction showed that certain
wavelengths of light relieved problems
of characters that shift or move during
reading activities.
• The same studies showed dysfunction
could be induced by certain
wavelengths of light presented during
reading activities. Can we extrapolate
to learners with CVI?
• Some students, especially those with
CVI often become overwhelmed by
certain colors of light or specific
intensities of light, or combinations
of each. We have observed this when
students turn away from a lighted
task. Adults with certain brain
injuries do this as well.
• Some people are not as bothered by
the light or its color until they have
to perform a reading task, or use
small muscles in a task. Then, some
become overwhelmed. Why?
We must learn a little about the
physics of light
We can see only 3 colors of light.
But you say you can see more than 3
colors! You can see more than 16 mil.
In Addition, Science and
Observation have shown:
• Blue light makes the visual system work
2,000,000,000,000 (2 trillion) times harder than red
light and billions of times harder than green light.
• Ultraviolet makes it work even harder, processing
quadrillions more waves per second, even though we
can’t see it.
• Learners with CVI most often prefer red and yellow
toys, tools, paper, crayons. Why do you suppose that
is? Are they selecting by comfort? By best vision?
Does she choose colors based
upon what makes her
comfortable?
In my practice, I have tested:
• Visually impaired learners 6 months to 100 years,
most were found to be very sensitive to blue and
ultraviolet light, some more than others.
• Generally, children and adults with CVI and
children with very immature neurological and
visual systems worked more efficiently for longer
under red, yellow, and sometimes green light.
They also preferred working under red or yellow
light, and maintained their preferences over the
period I worked with them.
Follow up, 10-12 years after testing
has shown:
• All but two of the 94 that preferred to work in
red light, still do.
• Of the twenty three that preferred yellow
light, all still do.
• Of the 10 that preferred green light, 7 now
prefer yellow. The other 3 are migraine
sufferers.
Three primary ways you can help:
• Eliminate blue light from the working
environment. This means changing the color
of the walls and floors as well as the lamps.
• Add red light to the learning environment.
• Allow the client to show you his/her light
preference through his/her filter choices and
alternatives presented during functional vision
assessment.
Before you add color to the
environment of a learner with CVI or
an immature visual system,
• Make sure the learner is rested, well-fed, calm
and ready to learn.
• Ascertain what his/her favorite color is (This does
not apply to adults.)
• Use that color as a guide for what color works for
your learner during educational activities
• Situate your learner in a place where the light is
dimmable.
• Be prepared to switch from overhead light to
flashlight or headlamp.
So let’s say you are a little
child with CVI…
Like Lindabelle Saylor
You are easily overwhelmed by bright
light, and you become downright wild
in the presence of blue light.
• The people who educate you are not aware of
lighting limitations for children with CVI. They
put you here.
Or worse, here:
Can learners like Lindabelle benefit
from sensory stimulation rooms at all?
• Even appropriately lit sensory rooms usually
have too much overall stimulation going on.
Yes, if we focus on one appropriately
colored thing at a time, and rest in
between.
What about Adults?
This is Diego. He has a job
but needs better working
conditions. His employer
made the decision to put him
in a place where he thinks
Diego will be better off.
HERE
where there is lots of artificial daylight.
Killer Garage!!! Daylight tubes, 6000 K
What would be a better place for Diego?
Some principles to remember are:
• Simplify
• Remove blue
• Use black, grey
and white
• Use yellows,
reds for accent
• One large
geometric pattern
• Fit overhead lights
with 2700 to 3200K
lamps
• Provide place
for retreat from light
Friendly Rehab Center Kitchen
•Color and contrast
differences among
floors, cabinets,
countertops, etc.
•Overhead lights are
fitted with 3200 K.
that give off a
slightly orangey
glow.
Another excellent kitchen
Even Better Kitchen
•Good contrast among all
surfaces.
•Bullseye design on the
cabinet doors helps define
each door.
•Patterned rug helps lead
user to sink.
•Yellow and pink colors are
easy on the eyes.
•Doorless cupboards help
define the cupboard space.
Friendly Rehab Exercise Room
An typical manufacturing
environment.
A better manufacturing environment
Things you can do to eliminate blue
light from the work or learning
environment:
• Replace cool white, full spectrum, daylight
tubes and lights with warm white (2700K)
• Provide clientele with filters to wear
Suggest topaz filters.
http://www.noir-medical.com/filters/47.html
Topaz filters are good because they allow the
wearer to use both cone vision and rod vision
during daylight hours. They also block all the
blue and ultraviolet light.
Provide dim light environments for
clients who are bothered by typical
levels of light.
• This is easily achieved by putting in dimmer
switches, and providing a flashlight or task
light.
• Provide tinted windows.
• Provide walls in warm colors.
You want an environment like this.
Not like this:
It takes time to implement these
changes. So lets get started!
We owe it to our consumers.
Mrs. Cho, who has retinitis
pigmentosa, is still
employed at age 84.
she is famous for her
wedding cakes.
Now I must go to get ready for my real job!
Resources
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• Bradnam, M.S., Montgomery, D. M., Moseley, H., &
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blue-light hazard during indirect ophthalmoscopy and
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• Chen, E. (1993). Inhibition of cytochrome oxidase
and blue-light damage in rat retina. Graefe’s Archive
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• Chou, B. R. (n.d.). Ocular health and the atmospheric
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Resources
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