Sclera
- The sclera, which is also called the tunica albuginea oculi, is the protective outer layer of the human eye that appears white. It is composed of elastic and collagen fibers. The sclera’s visibility aids in identifying where someone is looking, and it provides a foundation for the attachment of ocular muscles and the maintenance of the spherical shape of the eye.
- The color of the sclera contrasts with that of the iris in humans, but in some other vertebrates, the sclera is the same color as the iris. The sclera can indicate jaundice if it appears yellow or pale in color.
- The sclera is a dense connective tissue that makes up the majority of the surface area of the eye, including the region surrounding the cornea and extending to the optic nerve at the back of the eye. It is composed of collagen fibrils that are randomly arranged and interwoven, providing strength and flexibility to the eyeball. The thickness of the sclera ranges from 0.3 mm to 1.0 mm.
- While the sclera is metabolically inactive, it plays an important role in maintaining the shape of the eye and protecting it from damage and harmful substances. It has a limited blood supply and is opaque, but can turn yellow during jaundice or black during kidney and liver failure. Scleritis, which is inflammation of the sclera, is a serious condition.
- The sclera is subdivided into four components, namely, the episclera, stroma, lamina fusca, and endothelium.
Difference Between Sclera And Conjunctiva
The human eye is a crucial body part consisting of several structures, including the iris, pupil, cornea, sclera, and conjunctiva. The conjunctiva and sclera are two essential components of the eye’s defense system. The conjunctiva is a thin layer of tissue that lines the eye and eyelids and helps maintain a balanced tear film while also providing protection against foreign objects and infections. The sclera, on the other hand, is a sturdy connective tissue composed of collagen and elastin that surrounds and gives the eye its shape. The sclera connects to the cornea at the front of the eye and joins with choroidal tissue at the back of the eye via the optic nerve. Maintaining the integrity of both the conjunctiva and sclera are vital for the overall health of the eye, as abnormalities or inflammation can lead to significant disruptions in the ocular system.
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