Question

Lens and cornea do not have a blood supply. They are supplied with nutrients by
(a) Vitreous humor
(b) Aqueous humor
(c) Blindspot
(d) Retina

Answer 1

Hint: Cornea is the outermost layer of the eye and is transparent in nature. It protects the iris, pupil, and anterior chamber of the eye. The eye lens is a lens-like structure present in the anterior portion of the eye and is responsible for focussing images on the retina.

Complete Answer:
Cornea is the anterior portion of the layer called sclera which forms the outermost layer of the eye. The cornea is made up of dense connective tissue and is responsible for focusing light along with the eye lens. The lens is a transparent crystalline structure that is held in place by the ligaments attached to the ciliary body. Both these structures are not supplied with blood vessels but instead, a thin watery fluid fills the space between the cornea and the lens (aqueous chamber). This fluid is known as aqueous humor and is responsible for supplying nutrients and nourishment to these structures.

Additional information: Let us look at the other structure of the eye mentioned in the options.
Vitreous humor: The space present between the eye lens and the retina is known as the vitreous chamber and it is filled with a transparent gel-like fluid known as the vitreous humor.
Blindspot: Blindspot is the position in the retina where optic nerves leave the eye and blood vessels to enter the eye. This spot does not have any rod or cones cells present and thus no image is formed here.
Retina: The retina is the innermost layer of the wall of the eye and consists of three layers of cells known as ganglion cells, bipolar cells, and photoreceptor cells. These are arranged from inside to outside.
So, the correct option is ‘(b) Aqueous humor’.

Note:
- Eyes are located inside the sockets of the skull known as orbits.
- The wall of the eye is composed of three layers known as sclera (external layer), choroid (middle layer), and retina (inner layer).
- The anterior portion of the choroid layer becomes thick to form the ciliary body which continues forward to form a pigmented structure known as the iris.