How Color Vision Testing Works


Seeing our world in
color can be something many of us take for granted. For example, most of you
can tell that my shirt is orange without much thought. But that’s not always the case for people who are colorblind. So, in this week’s How it Works, I’m getting a look at how
our eyes help us see color and how doctors can tell
if someone is colorblind. (exciting rhythmic music) Today we’re getting some
insight into our eyes and we’re gonna talk
about colorblindness. So, I am with Doctor Volpe, who’s got all the
answers for us. I think before we start
talking about what colorblindness is, we
need to talk about how the eyes see color. – Sure, the perception of
color actually, of course, involves the whole
eye, in your retina, where you have three
different types of cones that are sensitive to
different visual pigments that all are sensitive
to different colors, red, green, and blue. And the composite of
putting the signals from those cells together
makes color, which is actually ultimately
perceived in our brain. – So, explain colorblindness. Is it that those signals,
all of the signals, are not working? – So, colorblindness falls,
generally, into two categories. One category is the kind
that you’re born with. They’re missing a specific
gene that’s responsible for the photo pigment in those
specific cells in the retina. So, they don’t have the
ability to send a different signal to the brain, and that’s where the confusion
between red and green or blue and yellow can occur. There are certain diseases,
specifically diseases of the optic nerve, the retina, and some of the degenerative
diseases that affect the brain that can cause you to
lose color vision in one or both eyes is an
acquired problem. And that’s why we often
screen for color blindness as part of figuring out
why people don’t see and what kind of vision
problems they may have. – So, if you’re colorblind, I would assume that it’s
gonna affect your daily life. – TO the extent that they
can (mumbles) recognizing red and green traffic lights,
looking at instrumentation. Those are situations in
which color may be affected. We should point out that
colorblind doesn’t mean that the world appears
black and white. It’s just that the hues
have less intensity. People who are
colorblind may see things in a different spectrum, but they may actually
have trouble telling a red light from a green light, with just some
modifications that people have to be careful. – I would love to take the test. – Okay, let’s do it. You’ll see, it’s just a
series of dots and designs that have different
colors that accentuate one’s ability to distinguish
one image within another. And then we simply ask
the patient to tell the number that they see. – [Jane] 12. – All right, so that
means we see well enough. – [Jane] Seven. 45. – Good, now we switch
to the other eye because we always wanna
test one eye at a time. I would generally do four
or five with each eye just to (mumbles) to
make sure they’re not doing a memory test. (laughing) – Eight, five. 29, 45. Two. Nothing. – Nothing, good. And that’s how I
assess color vision. – Cool, the biggest
takeaway is if you are maybe doing your own test or
you’re seeing something that’s concerning to you,
as far as your vision and even seeing color,
then see a doctor. – Sometimes it’s
described as a patient, things look washed out or gray, or dark with one of my eyes. That’s a very important
observation to make and to see an ophthalmologist. – And this test, really
simple, really easy, no pain. – No pain. – Love it, thank you so much. Great information. For more information on how
medical procedures work, just go to our website,
LIvingHealthyTV.com.

5 comments

  1. Please give me advices cuz I’m only 10 years old I see darker colour on my left eye then I see lighter colour on the right eye I never said this to my parents

  2. I love how I'm colour blind and when she said as u can see my shirt is orange I was like nooo wayyy orange really

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