The retina is the place where the image is formed ...its actually the blind spot on the surface of the retina. hence the person cannot see if it is damaged
there is no relation with the damage of retina and blind spot. every eye has blind spot.
but the blind spot is the place in which the image is formed in an inverted manner
no blind spot is the place where no rods and cones are present. no images form on a blind spot.
It is because the retina consists of rods and cones which are responsible for the intensity and colour of light. 

hence when the retina is damaged these also get damaged and hence the person is not able to se.
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