Essay On Sclera

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The eye is an important sensory organ for vision which houses a sensitive optical apparatus in a relatively isolated tissue compartment. Eye is essentially made of three layers: (1) sclera, (2) uveal tract, and (3) retina with each of these layers performing intricate duties which ensure proper functioning of the eye.
Sclera is an outer fibrous layer which mainly provides the mechanical stability to protect the eye and its sensitive optical apparatus. Sclera is mainly composed of collagen and elastic fiber and their irregularity gives sclera an opaque appearance. The most important function of sclera is to offer resistance to internal and external forces and to provide attachment for the extraocular muscle insertions. The scleral surface area in humans is …show more content…

Each component of this ensemble has a specific function. For example, iris acts as a variable aperture to control the light that enters the eye and ciliary body secretes aqueous humor. The vascular layer is the choroid, which provides blood supply to the retina. The iris arises from the anterior face of the ciliary body and is a forward extension of the choroid. The central aperture in the iris is called the pupil and its size is controlled by the iris to regulate the amount of light that enters the eye. The iris is made up of two types of muscles dilator and sphincter muscles. Sympathetic nervous system innervates dilator muscles and parasympathetic nervous system innervates sphincter muscles. Mydriasis which is dilation of the pupil is a result of increase in dilator muscle activity. Miosis the constriction of the pupil is a result of increase in sphincter muscle activity. The ciliary body consists of smooth muscle, which is innervated by the parasympathetic nervous system. When ciliary muscle contracts, the lens become more convex to accommodate proper vision. The other important function of the ciliary body is the production of aqueous humor, which

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