Light and dark adaptation of the eye

Discussion in 'Eye-Care' started by Tim Allen, Oct 14, 2006.

  1. Tim Allen

    Tim Allen Guest

    Hello,

    I´d like to know if someone can help me with the following: Is it true
    that the rods (during dark adaptation) and the cones (during light
    adaptation) on the retina do all adapt to the same ambient light level
    or do they just adapt to whatever light intensity hits them? If the
    latter should be right this mechanism could be a powerful tool to
    strech the eyes ability to deal with the enormous variations in light
    intensity that we are exposed to. As I´m not totally shure that this
    is the right group for this question I do cross-post it to
    bionet.neuroscience.

    However, thanks a lot for your answers!
    Tim Allen
     
    Tim Allen, Oct 14, 2006
    #1
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  2. Tim Allen

    p.clarkii Guest

    I'm not sure exactly what you are asking. but indeed light and dark
    adaptation is exactly the reason that the human eye is able to function
    over a range of approximately 5 log units of light intensity.

    anyway a little web searching will give you the answers that you seek.
    here is a site you should look at first as it is easy to understand and
    quite succinctly accurate.

    http://webvision.med.utah.edu/light_dark.html
     
    p.clarkii, Oct 15, 2006
    #2
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  3. Tim Allen

    p.clarkii Guest

    I believe there are many other mechanisms involved in light/dark
    adaptation aside from photopigment content. such factors include
    calcium regulation, opsin phosphorylation, post-receptor neural
    mechanisms derived from electrical interactions from other cell-types
    in the retina, switching between the cone and rod photoreceptor-based
    systems, etc. This is quite a complicated area of study in vision
    research.

    ===========
     
    p.clarkii, Oct 15, 2006
    #3
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