Outer Layer Of The Eye

By Eyecare NG

Overview | Wall of the Eye | Inner Parts | Accessory Structures

Overview

The eye is ane of the sense organs of the trunk. It is responsible for sight. This page contains a description of the structure of the eye and its components

The center is like a ball with most office of it sitting in a hole in the skull known as eye socket or orbit. The eye has a multilayered wall and the space inside it contains the lens and the fluids that help to keep the middle in shape.

In the orbit, the eye is surrounded by orbital fats and fibrous tissues that absorber it, as well equally extraocular muscles that motion it to different directions. In front, the eye is protected by the eyelids, conjunctiva and the lacrimal arrangement.

The wall of the eye

The wall of the middle is made upwardly of three layers namely:

The outer layer, which consists of the cornea and sclera
The centre layer, which consists of the iris, the ciliary body and the choroid
The inner layer, which consists of the retina

The outer layer

This is fabricated up of thick fibrous tissues that protect the inner structures of the eye. The outer layer consists of the cornea and sclera.

Cornea

This is the transparent structure at the front end of the centre. It is located in front of the pupil. Its major function is to bend light rays entering to the eye to enable them focus on the retina. Therefore, it is the main refractive surface of the eye and provides most of its focusing power.

Sclera

This is the white coat of the eye. Information technology is the toughest structure of the centre and serves to protect the eye from penetrating injuries. It helps in maintaining the shape of the eyeball together with the fluid in the eye. It also provides attachments for the muscles that control middle movements.

The eye layer

The middle layer is the vascular role of the center. Information technology is known equally the uvea and consists of the iris, ciliary body and choroid.

Iris

This is the coloured part of the eye. It has a rich supply of blood vessels and contains muscles that control the size of the educatee (the opening in the iris through which light enters the middle). One of the muscles known as dilator causes the student to widen in dim light. Another muscle known as sphincter muscle, causes the pupil to tuck in bright light. The corporeality of paint in the iris determines the colour of the eye. The major function of the iris is to control the amount of light entering the heart.

Ciliary trunk

The ciliary torso is the part of the middle layer of the middle connecting the iris to the choroid. It is attached to the crystalline lens by ligaments and holds the lens in place behind the pupil. Information technology contains muscles that control the ability of the lens to change its focusing power at unlike distances (a procedure known as accommodation). It likewise produces aqueous humour (the fluid that fills the anterior chamber of the middle and maintains intraocular pressure).

Choroid

The choroid is the posterior part of the centre layer of the center. Information technology is a connective tissue richly supplied with blood vessels and fretfulness. Its major function is to provide diet for the retina and the sclera.

Inner layer

The inner layer of the centre is the most sensitive function of the center known equally retina.

Retina

The retina is the nigh sensitive office of the eye. It is responsible for visual perception. It consists of nervous tissues with multiple sensitive cells that all work together nether normal weather to produce adept vision. On the retina, there are two major lite-sensitive cells (photoreceptors) responsible for vision. These are the rods and cones. The rods are responsible for nighttime vision while the cones are responsible for coloured daylight vision. Sensations received by these photoreceptors are transmitted through the optic nerve (a cranial nervus) to the brain where they are interpreted.

The inner part of the eye

The inner part of the eye is the surface area surrounded by the 3 layered wall. Information technology contains the lens and spaces (chambers) filled with aqueous and vitreous humour.

Lens

The lens is a transparent oval-shaped structure in the eye. It is held in place behind the people by ligaments fastened to the ciliary body. It focuses light rays entering the middle on the retina.

Aqueous sense of humor

The aqueous humour is one of the fluids in the centre. It is produced by the ciliary body and fills the spaces in the anterior part of the eye; that is the space between the cornea and the iris (anterior chamber) and that between the iris and the lens (posterior bedchamber). Aqueous sense of humour provides nutrients for the cornea and lens and helps to keep the centre in shape.

Vitreous sense of humour

The vitreous humour is the fluid that fills the space betwixt the lens and retina, known as vitreous chamber. It protects the retina and keeps information technology in place. It also helps the eye maintain its shape.

Accessory structures

These are structures external to the eyeball that work with other components of the eye to ensure good vision. They include conjunctiva, eyelid, lacrimal organisation and extraocular muscles.

Conjunctiva

This is a sparse layer of transparent tissue that covers the sclera and lines the inner surface of the eyelid. It lubricates the centre and serves as a protective barrier for the front end surface of the center.

Eyelid

The eyelid is the fold of peel that covers the eye and protects it from environmental hazards and injury.

Lacrimal system

This consists mainly of the lacrimal gland, lacrimal sac and nasolacrimal duct which respectively produces, reserves and drains the tears that lubricate the eyes.

Extraocular muscles

These are six muscles within the orbit that are attached to the outer layer of the wall of the eye at different positions. They go on the middle in identify and are responsible for moving the centre to different directions.