If the receptors were at the front of the retina, the pigment cells would have to be between them and the next layer of nerve cells, in a region already packed with axons, dendrites, and synapses. As it is, the layers in front of the receptors are fairly transparent and probably do not blur the image much.
The definition of impervious is not being able to be penetrated or not able to be hurt. 1  An example of impervious is a fabric that does not allow any liquid to pass through. 2  An example of impervious is a figurine made out of indestructible material.
Examples of impervious in a Sentence. â¦ Berlin struck me, above all, as impervious to any political reactions whatever â¦ âStephen Spender, New York Times Magazine, 30 Oct.1977. He looked at her, impervious to her tears â¦ âJean Stafford, Children Are Bored on Sunday, (1945) 1953.