How to Find Your Blind Spot
Every human eye has a blind spot where the optic nerve leaves the eye. It is a small area near the center of the retina and because the optic nerve occupies this area there are no retinal cells – no light-sensitive cells which can receive images. This area is called the optic disc.
In daily life we don’t notice the blind spots of each eye because the two eyes work together and each compensates for the other’s blind spot.
What to Do
- On a piece of white paper, draw two things next to each other horizontally, three to four inches apart:
- On the left side, a square about one-quarter of an inch wide, filled in with solid color
- On the right side, a circle, also about one-quarter of an inch wide and filled in
- Hold this paper at arm’s length and close your left eye.
- Look at the square with your right eye and gradually move the paper closer to your face.
At first you can see both the square and the circle. But at some point as you move the paper closer, the circle will disappear. It has reached the blind spot in your right eye. Instead of that circle, there is just white paper. You can repeat this experiment with your right eye closed to find your left eye’s blind spot.
Are you wondering how come you can see white paper if you can’t see the circle? That is because your brain knows the circle is on white paper and is therefore filling the empty space in with the same white. In the absence of any information coming from the right eye about that spot, your brain automatically fills the emptiness with what surrounds it.
- You can play with this phenomenon by drawing your square and circle on a piece of colored paper. Then the brain will fill the empty spot with that same color.
First Variation on This Experiment
- On a piece of white paper, draw the same quarter-inch square filled in
- To the left of the square, draw three items:
- The same quarter-inch circle filled in
- Two filled-in rectangles, one on each side of the circle, each about an inch and a quarter long and a quarter-inch high. Leave about two inches between the square and the nearest rectangle to the left of it.
- Hold the paper at arm’s length and close your right eye. Focus your left eye on the little square.
As you move the paper closer, the circle will disappear and the two rectangles will merge. Your brain has filled in the empty space by extending the rectangles across it until they meet.
Second Variation on This Experiment
- On a piece of white paper, draw the same little square on the left side
- Leaving a space of about two inches to the right, draw 25 circles in a square pattern – five across and five down. Put them close to each other but not touching. Color the center one any color of your choice and the other 24 another color of your choice but all the same color. So now the center circle stands out in its own color.
- Close your left eye and focus on the square with your right eye. Again move the paper gradually closer.
At some point the center circle will change color and match the other 24 circles. In this experiment the brain has used the surrounding pattern, rather than a solid color, to fill in the blind spot.
Our eyes are very complex and capable. For another interesting experiment, please see How to Find Your Dominant Eye.
Although the design of our eyes is perfection, no human eye is actually perfect. We all have tiny aberrations in the eye contours which distort vision at least a tiny bit, even in 20/20 eyes. Wavefront technology can detect them and express them in two colored, 3-D maps for your LASIK surgeon.
The subsequent Custom LASIK treatment corrects them, being based on this diagnosis. It will give you clearer vision than any glasses or contact lenses could have given you. Custom LASIK also gives better vision, especially better night vision, than traditional LASIK can give, being based on this more detailed and precise diagnosis.
Please use the map on this Contact Page if you would like to find a well-qualified LASIK surgeon in your area.