Virtually, every being rely on their eyes to see and make sense of the world around them. Your eyes are a vital part of your health.
In this article, I'll be enlightening you on the features of the eye, the defects, diseases and how you can care for your eyes. Please, Read to the end.
Structures auxiliary to the eye
The orbit
The eye is protected from mechanical injury by being enclosed in a socket, or orbit, which is made up of portions of several of the bones of the skull to form a four-sided pyramid, the apex of which points back into the head.
The optical foramen, the opening through which the optic nerve runs back into the brain and the large ophthalmic artery enters the orbit, is at the nasal side of the apex; the superior orbital fissure is a larger hole through which pass large veins and nerves. These nerves may carry nonvisual sensory messages e.g; pain or they may be motor nerves controlling the muscles of the eye. There are other fissures and canals transmitting nerves and blood vessels. The eyeball and its functional muscles are surrounded by a layer of orbital fat that acts much like a cushion, permitting a smooth rotation of the eyeball about a virtually fixed point, the centre of rotation. The protrusion of the eyeballs—proptosis—in exophthalmic goitre is caused by the collection of fluid in the orbital fatty tissue.
The eyelids
It is vitally important that the front surface of the eyeball, the cornea, remain moist. This is achieved by the eyelids, which during waking hours sweep the secretions of the lacrimal apparatus and other glands over the surface at regular intervals and which during sleep cover the eyes and prevent evaporation. The lids have the additional function of preventing injuries from foreign bodies, through the operation of the blink reflex. The lids are essentially folds of tissue covering the front of the orbit and, when the eye is open, leaving an almond-shaped aperture. The points of the almond are called canthi; that nearest the nose is the inner canthus, and the other is the outer canthus. The lid consist of layers, they include:
The skin, containing glands that open onto the surface of the lid margin,
The eyelashes; a muscular layer containing principally the orbicularis oculi muscle, responsible for lid closure; a fibrous layer that gives the lid its mechanical stability, its principal portions being the tarsal plates, which border directly upon the opening between the lids, called the palpebral aperture; and the innermost layer of the lid, a portion of the conjunctiva. The conjunctiva is a mucous membrane that serves to attach the eyeball to the orbit and lids but permits a considerable degree of rotation of the eyeball in the orbit.
Visual defects and correction.
Myopia or nearsighted
Hyperopia or faresighted
This vision problem occurs when light rays entering the eye focus behind the retina, rather than directly on it. The eyeball of a farsighted person is shorter than normal.
Farsightedness can be corrected with glasses to change the way light rays bend into the eyes. If your glasses begins with plus numbers, like +1.50, you are farsighted.
ASTIGMATISM
Instead of the cornea having a symmetrically round shape (like a tennis ball), it is shaped more like a rugby ball, with one meridian being significantly more curved than the meridian perpendicular to it.
Astigmatism usually causes vision to be blurred or distorted to some degree at all distances. Symptoms of uncorrected astigmatism are eye strain and headaches, especially after reading or other prolonged visual tasks. This defect is usually combined with Myopia or Hyperopia.
PRESBYOPIA
Presbyopia generally is believed to stem from a gradual thickening and loss of flexibility of the natural lens inside your eye
Presbyopia usually occurs beginning at around age 40, when people experience blurred near vision when reading, sewing or working at the computer.
Common Eye Disorders and Diseases
1. Refractive Errors.
2. Age-Related Macular Degeneration.
3. Cataract.
4. Diabetic Retinopathy.
5. Glaucoma.
6. Amblyopia.
7. Strabismus.
Cataract
Cataract is a clouding of the eye’s lens and is the leading cause of blindness worldwide, and the leading cause of vision loss in the United States. Cataracts can occur at any age because of a variety of causes, and can be present at birth. Although treatment for the removal of cataract is widely available, access barriers such as insurance coverage, treatment costs, patient choice, or lack of awareness prevent many people from receiving the proper treatment.
Diabetic retinopathy
Diabetic retinopathy (DR) is a common complication of diabetes. It is the leading cause of blindness in American adults. It is characterized by progressive damage to the blood vessels of the retina, the light-sensitive tissue at the back of the eye that is necessary for good vision.
Glaucoma
Glaucoma is a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness. Glaucoma occurs when the normal fluid pressure inside the eyes slowly rises. However, recent findings now show that glaucoma can occur with normal eye pressure. With early treatment, you can often protect your eyes against serious vision loss.There are two major categories “open angle” and “closed angle” glaucoma. Open angle, is a chronic condition that progress slowly over long period of time without the person noticing vision loss until the disease is very advanced, that is why it is called “sneak thief of sight.” Angle closure can appear suddenly and is painful.
Amblyopia
Amblyopia, also referred to as “lazy eye,” is the most common cause of vision impairment in children. Amblyopia is the medical term used when the vision in one of the eyes is reduced because the eye and the brain are not working together properly. Conditions leading to amblyopia include strabismus, an imbalance in the positioning of the two eyes; more nearsighted, farsighted, or astigmatic in one eye than the other eye, and rarely other eye conditions such as cataract.
The national library of medicine recommends a few important things you can do to help keep your eyes healthy and make sure you are seeing your best:
1. Eat a healthy, balanced diet.
2. Maintain a healthy weight.
3. Get regular exercise.
4. Wear sunglasses.
5. Wear protective eye wear.
6. Avoid smoking.
7. Know your family medical history.
8. Know your other risk factors.
9. If you wear contacts, take steps to prevent eye infections;
Wash your hands well before you put in or take out your contact lenses. Also follow the instructions on how to properly clean them, and replace them when needed.
10. Give your eyes a rest. If you spend a lot of time using a computer, you can forget to blink your eyes and your eyes can get tired. To reduce eyestrain, try the 20-20-20 rule: Every 20 minutes, look away about 20 feet in front of you for 20 seconds.
Take proper care of your eyes; if you notice strange developments in them, make sure to consult the eye doctor(optician) immediately. As often as necessary, avoid self-medications when dealing with your eyes.
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