Know About Your Eyes & It's Common Problems
In a human body the eye is a very small organ. Although it is small, the eye is a complex organ. To enable clear vision, all structures within the eye must function properly in order to capture light, focus it, and relay messages back to the brain to create a visual image. This complexity is what makes eye anatomy such a fascinating subject.
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What Makes up an Eye:
Iris: It regulates the amount of light that enters our eye. It forms the coloured, visible part of our eye in front of the lens. Light enters through a central opening called the pupil.
Pupil: The circular opening in the centre of the iris through which light passes into the lens of the eye. The iris controls widening and narrowing of the pupil.
Cornea: The transparent circular part of the front of the eyeball. It refracts the light entering the eye onto the lens, which then focuses it onto the retina. The cornea contains no blood vessels and is extremely sensitive to pain.
Lens: A transparent structure situated behind our pupil. It is enclosed in a thin transparent capsule and helps to refract incoming light and focus it onto the retina.
Choroid: The middle layer of the eye between the retina and the sclera. It also contains a pigment that absorbs excess light so preventing blurring of vision.
Ciliary body: The part of the eye that connects the choroid to the iris.
Retina: A light sensitive layer that lines the interior of the eye. It is composed of light sensitive cells known as rods and cones. There are between 6 and 7 million cones in the eye and they are essential for receiving sharp accurate image and for distinguishing colours. The retina works much in the same way as film in a camera.
Macula: A yellow spot on the retina at the back of the eye which surrounds the fovea.
Fovea: Forms a small indentation at the centre of the macula and is the area with the greatest concentration of cone cells. When the eye is directed at an object, the part of the image that is focused on the fovea is the image most accurately registered by the brain.
Optic disc: The visible portion of the optic nerve, also found on the retina. The optic disc identifies the start of the optic nerve where messages from cone and rod cells leave the eye via nerve fibres to the optic centre of the brain. This area is also known as the ‘blind spot’.
Optic nerve: Leaves the eye at the optic disc and transfers all the visual information to the brain.
Sclera: The white part of the eye, a tough covering with which the cornea forms the external protective coat of the eye.
Rod cells: These are one of the two types of light sensitive cells in the retina of the eye. There are about 125 million rods, which are necessary for seeing in dim light.
Cone cells: Cone cells are the second type of light sensitive cells in the retina of the eye. The human retina of the eye. The human retina contains between six and seven million cones, they function best in bright light and are essential for acute vision.
Common Eye Problems
Refractive Errors (Vision Problems) – Refractive error means that the shape of your eye does not bend light correctly, resulting in a blurred image. The refractive error is also known as refraction error. The main types of refractive errors are Myopia (Near-sightedness), Hyperopia (Farsightedness), Presbyopia (Loss of near vision with age) and Astigmatism. This refractive error is one of the common problem. Most refractive errors can be corrected with eyeglasses or contact lenses. Besides this surgery is also becoming a popular option to correct refractive errors.
Glaucoma – Glaucoma is a group eye conditions that damage the optic nerve, which is vital to good vision. This damage is often caused by an abnormally high pressure in our eye. Glaucoma is one of the leading causes of blindness. It can occur at any age but is more common in older adults. Vision loss due to glaucoma can’t be recovered. So it’s important to have regular eye exams that include measurements of our eye pressure. If left untreated, glaucoma will eventually cause blindness. There are five types of glaucoma- 1. Open angle glaucoma, 2. Angle closure glaucoma, 3. Normal tension glaucoma, 4. Glaucoma in children, 5. Pigmentary glaucoma.
Cataracts – A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the pupil. Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world.
Age related Macular degeneration – Age related macular degeneration is a problem with the retina of eye. It happens when a part of the retina called the macula is damaged. With age related degeneration victim can lose their central vision. Victim cannot see fine details, whether victim are looking at something close or far. But our peripheral vision will still be normal. AMD is very common. It is the leading cause of vision loss in people 50 years or older. There are two types of AMD – 1. Dry AMD 2. Wet AMD
Diabetic Retinopathy – Diabetic retinopathy is a complication of diabetes, caused by high blood sugar levels damaging the back of the eye (retina). It can cause blindness if left undiagnosed and untreated.
Amblyopia – Amblyopia, also known as lazy eye, is a vision development disorder which an eye fails to achieve normal visual acuity, even with prescription eyeglasses or contact lenses. Amblyopia begins during infancy and early childhood. In most cases, only one eye is affected. But in some cases, reduced visual acuity can occur in both eyes. Particularly if lazy eye is detected early in life and promptly treated, reduced vision can be avoided. But if left untreated, lazy eye can cause severe visual disability in the affected eye.
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