Peripheral Vision Test

Another simple way to test your blind spot:

1. Close your left eye.

2. Extend your right arm in front of you, perpendicular to your body.

3. Stick your thumb up, parallel to your body. It should be aligned with your right eye.

4. Keep looking straight ahead and slowly increase the angle on your arm, moving it to the right.

Your thumb will disappear from view, though you can still see your arm. Invert the left/right positions in the instructions for the other side.

Wikipedia also has a quick test: https://en.wikipedia.org/wiki/Blind_spot_(vision)#Blind_spot...