Question

How do the sclera and cornea differ?

Answer 1

Hint: The visible white part of an eye at the front is called the sclera. It runs continuously with the cornea. The cornea is the outer transparent layer that covers the eye.

Complete answer:
The paired organs of the visual system located in the front part of our face are called the Eyes. They have a three-dimensional structure that is situated in the orbits of the skull. They are primarily responsible for providing vision in animals. They receive and detect light and send them to the brain as electrochemical signals. The eye has several structures, which can be divided into two categories depending on their position. External or visible structures of the eyes are-
1)Sclera
2)Conjunctiva
3)Cornea
4)Iris
5)Pupil

Internal structures of the eyes are-
1)Lens
2)Retina
3)Optical nerves
4)Aqueous humor
5)Vitreous humor

Cornea and Sclera are the parts of the external structures of the eye and are both connective tissues. They share the same collagen, and their junction is called the- Corneoscleral junction. The cornea is the bulging part of the eye that covers the- iris, pupil, and anterior chamber. They have an unmyelinated nerve ending, which provides them sensitivity towards any touch, temperature, and chemicals. The cornea acts as the outermost lens of the eye. It runs continuously with the sclera in the eye. The sclera is the outer fibrous connective tissue layer made up of collagen and fibers. It provides an attachment site for various muscles.

Table showing the differences between the Cornea and Sclera.

Cornea	Sclera
It is the transparent part of the eye.	It is opaque and white.
They have a uniform distribution and thickness of the collagen fibers.	The distribution and thickness of collagen fibers in the sclera are irregular.
Light enters the eye through the cornea.	It is opaque, and thus no light enters the eye through here.
Its main functions are to refract or bend the entering light and focus it according to our vision.	It is a tough fibrous layer that forms the external coating of the eye and protects the inner components of the eye by providing a structure for them.
It has five layers- the epithelium, Bowman’s layer, the stroma, Descemet’s membrane, and the endothelium.	It has four layers- the episclera, the stroma, the lamina fusca, and the endothelium.
They have more mucopolysaccharides.	They have lesser mucopolysaccharides.

Note: The discoloration of sclera is a very common phenomenon. With age, the color of the sclera can get darker, redder, and yellower- due to the deposition of lipids. During jaundice, the deposition of bilirubin results in the yellowing of the eye. Redding of the sclera- is caused by the dilated blood vessels.