Question

In the human eye, at the blind spot
(a) Only rod are present
(b)Only cones are present
(c)Both rods and cones are present
(d)Neither rods nor cones are present

Answer 1

They are the small portion of the visual field of each eye that corresponds to the position of the optic disk (also known as the optic nerve head) within the retina.

Complete answer:
Optic nerves are located at the posterior portion of the eyes. The optic nerves carry all the nerve impulses from the retina to the human brain for perception. Optic nerves are of two types which are cones and rods. Cones: Cones are the nerve cells that are more sensitive to bright light. They help in detailed central and color vision. Rods: Rods are the optic nerve cells that are more sensitive to dim lights. They help in peripheral vision. At the crossing of the optic nerve and retina, there are no sensory nerve cells. So no vision is feasible at that point and called a blind spot.

Additional Information: The parts of the eye which are seen from outside are includes-
-Sclera is a white visible portion. It is made up of dense connective tissue and protects the inner parts.
-Conjunctiva lines the sclera and is made up of stratified squamous epithelium. It keeps our eyes moist and clear and provides lubrication by secreting mucus and tears.
-Cornea is the transparent, anterior, or front part of our eye, which covers the pupil and the iris. The key function is to refract the light together with the lens.
-Iris is the pigmented, colored portion of the eye, visible externally. The key function of the iris is to control the diameter of the pupil as per to the light source.
-Pupil is the small aperture located in the center of the Iris. It permits light to enter and focus on the retina.
So, the correct answer is ‘Neither rods nor cones are present’.

Note: Much like the electronic device, the human eye also focuses and lets in light to produce images. So generally, light rays that are deflected from or by distant objects land on the retina after they pass by several mediums like the cornea, crystalline lens, aqueous humor, the lens, and vitreous humor.