Blind spot is called to because of
a)	The presence of photoreceptor cells	b)	Presence of optic nerves
c)	The absence of photoreceptor cells	d)	None of the above

(c)

The optic nerves leave the eye and the retinal blood vessels enter it at a point medial to and slightly above the posterior pole of the eyeball. Photoreceptor cells are not present in that region and hence it is called blind spot. At the posterior pole of the eye, lateral to the blind spot there is a yellowish pigmented spot called macula lutea with a central pit called the fovea. The fovea is a thinned-out portion of the retina where only the cones are densely packed. It is the point where the visual acuity (resolution) is the greatest