What does mean a blind spot.

Am watched  on TV about an eyes lecture, as about blind spot, why does she call, does it healthy or not.
As you know that on eye retina having receptors are sensitiveness to the light,thanks to theirs we are absorbing imagination, as also on retina having small side,where passing away is vision nerve, and in this zone without photo receptors, here calling a blind spot, this is not a pathology, in any person having such blind.And why you can to see,that enters in a vision field, without emptiness, therefore are blind spots in right and left hand finding are symmetrically, as receptors for one eye are building images,which cannot to see an other eye, as if you are  to see with one eye, thus are not initial eyes mobilities, small turning a head is enough, that in brain forming whole imagine.