Knowing your surrounds is key to your self-defense. So knowing where your blind spot can definitely help.
This is not meant as any sort of medical/eye tests, but it might shed some light on blindspots you weren’t aware of or had forgotten about. 
Here’s a fun way to check your blind spots: Blind Spot - Test - YouTube
Did you “see” your blind spots?
I recently found out everyone has a blind spot in each eye. Most of us will never notice it nor will it have any affect on your normal vision.
Glaucoma gives you a second blind spot (or can enlarge the one already there) in your eye/eyes and if it goes untreated it can get to a point where it will affect your vision. Glaucoma is not reversible (at this time) but once it is caught it can be treated so that its progression can be slowed way down. Depending on your age and when it is discovered you might never even know you have a second blind spot.
(I know all this because it was just explained to me in the last month after finding it in my right eye during an eye exam.)