This is perfectly safe, and I guarantee it will floor you if you haven’t seen it before. Forgive the pun – can’t help it.
This will depend on your monitor size, so let’s get set up here… Grab a ruler and measure the distance between the two big letters X O below. (READERS PLEASE NOTE: THIS COLUMN IS INTENDED FOR TOMORROW – I AM NOW FIDDLING WITH THE EDIT TO MAKE THE X AND O APPEAR ON THE SAME LINE FAR LEFT AND FAR RIGHT – IF THEY CURRENTLY DON’T, COPY INTO WORD AND SPACE OR BACKSPACE BETWEEN THEM TO MAKE THAT SO – TOM) Multiply that by 3.3 and move the tip of your nose to approx that distance from the screen. Cover your left eye and look at the X. The O should vanish. Cover your right eye and look at the O. The X should vanish.
Hints: If you are having trouble with this, try moving your head toward-away. There should be a distance at which the letter completely disappears. Also, you MUST look at the letter – that may take a bit of self control. Just relax into it. If exasperated, try putting two big spots on a sheet of paper 6 inches apart and hold it about 20 from your face. Adjust the distance until the spot disappears.
The trick is that we are all significantly blind but our brains are trained to not notice it. Each eye necessarily has a big blind spot where the optic nerve enters the retina. Since they are on opposite sides, they do not overlap – and we have no “two-eyed blind spot.” People with “ocular migraines” – temporary loss of vision – almost always experience a similar effect in both eyes simultaneously. This is impossible to ignore.
Let me know if you are having difficulty bringing it on. Lots of people find it hard to control. Tom
© 2012 Thomas Dey - 4/1/12