Introduction
Eyes are the window to our souls. Eyes play a major role in our daily lives. The importance of eyes can be known only when they are not functioning. Vision is the greatest gift of life. It can be devastating. But the vision is not damaged. Rather the different layers that make up an eye will get affected. Eyes are made up of several layers. Even if one layer gets affected, vision can get damaged greatly. This article will discuss the various layers of the eyes in detail and the conditions these layers are prone to.
What Is the Anatomy of the Eye?
The eyes perform one of the important senses, which is vision. Eyes are composed of layers, and fluid between the layers is collectively responsible for creating a vision.
The various layers of eyes are as follows:
1. Cornea -
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The cornea is the outermost layer of the eyes. It is a transparent layer covering structures like the eye's iris, pupil, and anterior chamber.
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The corneal layer is devoid of blood vessels and comprises proteins and cells. It is supplied with nutrition by the fluid and liquid parts of the eyes, such as tears and aqueous humor.
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The main function of the corneal layer is to bend the light and let it pass through the different layers of the eye to form an image for vision.
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The cornea is subjected to scratch injuries commonly. It heals on its own, but in some cases, scarring of the cornea can be seen.
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Keratitis, dry eyes, corneal dystrophies, and viral, bacterial, and fungal infections are a few conditions affecting the cornea.
2. Sclera -
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The sclera is the white part of the eye that covers the entire eyeball and is less than a millimeter thick. The transparent corneal layer lines this sclera.
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It is mainly composed of collagen fibers, which gives it strength.
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The main function of the sclera is to give shape to the eyeball and maintain its shape.
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Common medical conditions affecting the sclera are blue sclera, icteric sclera, injury, melanosis, pinguecula, pterygium, irritant allergy, and medication-induced allergies.
3. Iris and Pupil -
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Iris is the colored part of the eyes, and it contains the pupil in the center, which lets the light pass through to reach the layers at the back. Iris is a round structure.
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It is made up of muscles and nerves. These muscles of the iris layer will control the pupil's functioning if the pupil is wider or dilated. Otherwise, if it narrows. The pupil will control how much light should enter the eyes.
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The main significance of the iris is that each individual’s iris is different, just like their fingerprints. This explains the iris recognition technology used in many organizations in place of faces and fingerprints. The accuracy is measured to be around 99 %.
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Some conditions that affect the iris layer are albinism, cataracts, Horner’s syndrome, uveitis, Waardenburg syndrome, and albinism.
4. Lens -
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The lens is part of the eye that is present right behind the iris and pupil. It is a clear and curved structure. Behind the retina is the aqueous humor (fluid part) of the eye.
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It is commonly known as a crystalline lens and is predominantly made of proteins and collagen. It is devoid of blood vessels, and thus, it depends on the aqueous humor present behind it for nutrition.
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The main function of the lens is to focus the light received on the retina present at the back of the eyes. The lens is so flexible that it changes its shape and structure to focus on objects or things at different distances.
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The most common condition of the lens seen among the general population is cataracts. Cataracts are a condition affecting the aged population. As a person ages, the eye's clear lens becomes thick and translucent. Thus, an adequate amount of light will not enter the lens and will not reach the retina adequately, and thus blurry vision is noticed. This is a common reason why older adults cannot see things.
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Some other conditions that affect the eye's lens are congenital rubella syndrome, trisomy 13, Pierre-Robin syndrome, Down syndrome, and Lowe syndrome.
5. Aqueous Humor and Vitreous Humor -
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Aqueous humor is a clear liquid that fills up the front part of the eyes. This aqueous humor is then and there drained through the draining angle. However, if it does not get drained and builds up in the eye, the intraocular pressure will eventually rise, leading to conditions like glaucoma. Post-which, the vision gets damaged completely.
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Vitreous humor is a gelatinous part present between the lens and retina. It supports the retina and provides nutrition to the lens, devoid of blood vessels. In case of shrinkage of the vitreous body, the retina gets detached from the back of the eye and will result in major vision damage.
6. Retina -
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The light entering the eyes will be directed to the retinal layer of the eyes through the cornea, iris, and lens. The information is carried to the brain through the optic nerve. The brain will process the information; thus, an image is formed for vision. The center of the retina is made up of a macula.
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The retina is made up of cones and rod cells. Rod cells are the photoreceptor cells responsible for vision in dull lighting. Cones are color-processing cells and are responsible for producing color vision.
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Common conditions affecting the retina are retinal detachment, macular degeneration, retinitis pigmentosa, retinal vein occlusion, eye floaters, etc.
Conclusion
The eye is an important part of the body; thus, immense care should be taken to prevent infections and injuries. It is advised not to touch the eyes with bare hands and fingers. It is good to always wash our hands before dealing with eye-related functions.
