A to Z Challenge- Learn Something New Every Day




  • Rods and cones are the photoreceptor cells in the human retina.
  • Rods are responsible for letting us see in low levels of light, they don’t regulate color and are not very good at spatial acuity (ie our ability to discern two points in space)
  • Cones are active at higher light levels, they are particularly good at spacial acuity and color reception
  • *In the back of the eye where the optic nerve pierces the retina, there are no rods and cones
  • SO if light from an object lands on this spot* then the object will be invisible to the eye. This is called the optic disc or the blind spot
  • We don’t normally perceive the blind spot on a regular basis because our brain interprets the information it receives from our other eye and fills in the needed information to formulate a visual shape.

                   about theeye_howyousee_blind_1 source



R                                                                L




Close your right eye, look at the “L” with your left eye, and now move your eye toward or away from the screen until you notice the “R” disappear. Repeat on the other side. Once you move further past the blind spot in either direction, the letter will reappear.





29 thoughts on “A to Z Challenge- Learn Something New Every Day

  1. As Mr. Spock would say, “Fascinating!” You come up with the most interesting things, Ivy. Well done.
    Now, does Douglas have a similar “blind spot”?
    Blessings and Bear hugs, m’lady. Best regards to Douglas.


  2. How very interesting. I loved the experiment. It’s the other kind of blind spots that concern me more. You know – the ones in your thoughts, actions and emotions, that you don’t quite get a clear picture of.


      1. My migraines start out with a blind spot like you get if you look at a flashbulb when someone takes your picture. It moves from one side of my vision all the way across to the other (usually left to right). It also has squiggly lights in it, especially around the edges. That’s the part that makes me nauseous. The headache comes after the blind spot passes.


      1. well, I think is was a scene in the otherwise non-remarkable 80s horror movie Candyman…. (as opposed to Sammy…. wait! a minute!! he (Sammy Davis Jr not the Candyman) was blind in one eye! so that would be the ‘real’ link to the association, as opposed to the one I thought I was making!
        nicely wrought, Ms Candler-of-Heads, nicely wrought!

        Liked by 1 person

    1. yeah… (and, not remembering your current blog name, I still clicked on it… as a ‘hey this sounds like something that might be interesting*)

      * my god, not to be un-charitable, but have you surveyed the blogs in this incredible and wonderfully rogerian bloghop…. ayyiiee (I immediately stored the memory for the next time I feel like throwing the computer on the ground because I am so awful at blogging)…. lol


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s