Of all the five senses, sight is the most precious and miraculous sense. Any defect in the eyes or any harm caused to them handicaps a man to a great extent. The eye diseases are both of permanent and temporary nature. Do you know what are the common eye disorders and how are they caused?
Among the common disorders of the eye, myopia or short-sightedness and Hypermetropia or long-sightedness are the most common. In myopia, the light entering the eye is bent too much so that it focuses at a point in front of the retina. As a result a person can see the nearby objects well but can not see distant objects clearly. Whereas in Hypermetropia, the light is not bent sufficiently and focuses at a point behind the retina. Hence the patient sees distant objects well but near vision becomes difficult and causes strain. Corrective glasses are used to get a clear vision.
Conjunctivitis is another common disease of the eyes. It brings about an inflammation of the conjunctiva of the eyelids and the eye ball. It can be caused by allergy, irritation or infection. A viral form of conjunctivitis is called trachoma which is a major cause of blindness in Europe and Asia. Another infection of the eye is ‘sty’ that affects a gland at the corner of the eyelid. Cataract is a condition in which the lens becomes cloudy or opaque, reducing the amount of light that enters the eye. Its treatment may require surgical removal of lens, and then either implantation of an artificial lens or the use of special corrective glasses becomes necessary.
‘Glaucoma’ is an eye ailment that causes increased pressure within the eye ball which puts pressure on the optic nerve. If the pressure is higher than a certain level and not controlled, then it may lead to blindness. Night blindness is caused by the deficiency of Vitamin A, which results in the damage of special cells, called ‘rods’ that enable us to see in dim light. In a ‘retinal detachment’, the retina gets separated from the choroid and floats in the vitreous humor. This can be caused by a fall, a blow on the head or by any other trauma to the eye. It is treated surgically and in many cases laser beams are used to fix the retina back in place.
Sometimes the retina gets degenerated and leads to total blindness. The disease of retinal degeneration is called Retinitis pigmentosa. There is no treatment for this disease and it eventually leads to permanent blindness.
A corneal abrasion is a very painful scratch on the surface of the cornea. It usually heals automatically without causing any ill effects. Corneal scarring, however, results from a more severe injury or disease. Since scar interferes with or totally obscures the vision, the cornea may be removed and transplanted.