Question

Pigmented layer in the eye is called as
(a) Cornea
(b) Sclerotic
(c) Choroid
(d) All of the above

Answer 1

Hint: The retina makes up the inner layer of the eye. It occupies only the posterior two-thirds of the eye. It consists of several layers of cells, including the rods and cones, the sensory cells, that respond to light. Pigmented layer refers to the layer of the eye behind the retina, which contains blood vessels that nourish the retina. The tips of the rods and cones are embedded in a pigmented layer of cells on the back of the retina.

Complete answer:
The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, containing connective tissues, and lying between the retina and the sclera. It is referred to as the pigmented layer of the eye. The human eye is a sense organ that reacts to light and allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth.

The pigment helps prevent light from scattering in the back of the eye. The iris consists of two layers: the front pigmented fibrovascular layer known as stroma and, beneath the stroma, pigmented epithelial cells. The outer edge of the iris, known as the root, is attached to the sclera and the anterior ciliary body. The iris and ciliary body together are known as the anterior uvea. The eye is part of the sensory nervous system.

Additional Information:
- Retinal Pigmented Epithelium refers to a layer of cells that protects and nourishes the retina, removes waste products, prevents new blood vessel growth into the retinal layer, and absorbs light not absorbed by the photoreceptor cells.
- These actions prevent the scattering of the light and enhance the clarity of vision.
- Cornea: The outer, transparent structure at the front of the eye that covers the iris, pupil, and anterior chamber; it is the eye’s primary light-focusing structure. Sclera: The tough outer coat that protects the entire eyeball.
So, the correct answer is '(c) Choroid'.

Note:
- The human choroid is thickest at the far extreme rear of the eye. The choroid provides oxygen and nourishment to the outer layers of the retina.
- Along with the ciliary body and iris, the choroid forms the uveal tract. The choroid has several functions.
- Its vasculature is the major supply for the outer retina; impairment of the flow of oxygen from the choroid to the retina may cause Age-Related Macular Degeneration. The choroidal blood flow, which is as great as in any other organ, may also cool and warm the retina.