Wednesday, May 7, 2014

How Blind People Detect Light


You might think that detecting light is the key for having sight.  A recent study conducted at the University of Montreal says otherwise.

Professor Gilles Vandewalle and his colleagues at the University of Montreal conducted a study to test how well blind people could detect light.  Previous studies hypothesized that cells behind the retina of the eye can detect light even in those who are blind.  The big question is why?

During Vandewalle's study, he had three test subjects who were completely blind.  He would turn a blue light on and off and ask the subjects to determine when the light was on.  Surprisingly, the rate of correct answers was much higher than expected.  Vandewalle also discovered during his study that when someone is exposed to light, that triggers alertness in their brain cells.  Now, Vandewalle's theory is that brain cells are the ones that detect light.


NOS Themes

  • Science is collaborative
  • Importance of repeatability
  • Role of credibility

Read More:
http://www.scientificamerican.com/article/how-blind-people-detect-light/

4 comments:

  1. Interesting article! I wanted to know a little more about how light effects the brain and more specifically, the blue light. In this article it also states that light does not just aid vision but it also supports alertness and cognitive tasks. Many areas of the brain responded with blue light being the best result. If we think about it, blue light, or daylight, is most common, we just seem to ignore it.
    Researched Source:http://www.sciencedaily.com/releases/2007/11/071130232132.htm

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  2. I find it fascinating that blind people could still be able to detect light, even though they can't see other things. One question I have is what is the significance of the blue light? Would the experiment have similar results with a different color light being tested? The concept of brain cells detecting light instead of the cells behind your retina is very interesting to me. Being able to detect light is important, as it signifies whether it's night or day, which is important for brain activity.

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  3. I was very interested in the color of light used in this particular experiment. If one were to look up the visible spectrum of light, you would find that blue is on of the "pure colors" of light. What would happen if they tested the other pure colors? A pure color is a color that is visible, and only uses one wavelength. In the article mentioned by Madi, they say that they tested blue, violet and green. But they missed one pure color, red. Red, green and blue are the three pure colors and red is still untested. If red does not work, then possibly the brain can only respond to a specific wavelength. These are all hypotheses that would require further testing.

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  4. This was interesting. How is it that we can detect light without actual sight. If it is the brain cells detecting it, are they doing it on their own or using another sensory organ. I also have the same question as the people above me, is it possible that there is something special about blue? Is it possible that only certain wave lengths are able to be registered?

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