Computerized Physiologic Blind Spot Mapping
The Next Generation . . .
Free *Bonus Blind Spot Mapping System - (See "Free Blind Spot" Box Right Below)
Find Your Blind Spot

Close your left eye and stare at the cross mark in the diagram with your right eye. Off to the right you should be able to see the black spot. Don't LOOK at it; just notice that it is there off to the right (if it's not, move farther away from the computer screen; you should be able to see the dot if you're a couple of feet away). Now slowly move toward the computer screen. Keep focusing on the cross mark while you move. At a particular distance (probably a foot or so), the spot will disappear (it will reappear again if you move even closer). The spot disappears because it falls on the optic nerve head, the hole in the photoreceptor sheet, your blind spot.

So, as you can see, you have a pretty big blind spot, at least as big as the spot in the diagram. What's particularly interesting though is that you don't SEE it. When the spot disappears you still don't SEE a hole. What you see instead is a continuous white field (remember not to LOOK at it; if you do you'll see the spot instead). What you see is something the brain is making up, since the eye isn't actually telling the brain anything at all about that particular part of the picture.

How is Blind Spot Mapping Done?

You can easily do your own test at home. Tape a sheet of paper to the wall and make a small cross or + sign in the center of the sheet at eye level. If you are testing the right eye, close or cover your left eye.  From about a foot away, fixate on the + sign with right eye while covering the left eye. Take a small target (use a red ink pen and color a small portion of the corner of a 3 x 5 index card) and slowly move it horizontally from the cross or + sign to the right edge of the paper. At some point, the target will disappear from view when it enters into your blind spot, and then it will reappear when it exits your blind spot. You have now located the left and right borders of the right blind spot. By returning into blind spot and moving the target out in other directions, you can map its other dimensions by marking the paper at the points where the target seems to reappear. Your finished map will look something like this:


    Left Eye  

Right Eye     

If you perform this test on graph paper, you can count the number of graph squares in each blind spot, or you can measure the distance between all the reference points and calculate the circumferences of each blind spot. In the above example, you can discern that the left blind spot is slightly larger than the right blind spot.

Or go to: an interactive way of mapping your blind spots.

_____________________________________________________________________________   -   Int'l Phone: 530.949.1353