Sometimes some people may develop eye problems due to poor lifestyle and habits and balanced diet, old age or heredity. Some common defects are myopia hypermetropia and cataract.
Write a short note on each of the above given eye defects.
Answers
Explanation:
Nearsightedness, or myopia, as it is medically termed, is a vision condition in which people can see close objects clearly, but objects farther away appear blurred. People with myopia can have difficulty clearly seeing a movie or TV screen, a whiteboard in school or while driving.
Myopia occurs if the eyeball is too long or the cornea (the clear front cover of the eye) is too curved. As a result, the light entering the eye isn't focused correctly, and distant objects look blurred.
Myopia affects nearly 30 percent of the U.S. population. While the exact cause of myopia is unknown, there is significant evidence that many people inherit myopia, or at least the tendency to develop myopia. If one or both parents are nearsighted, there is an increased chance their children will be nearsighted.
Even though the tendency to develop myopia may be inherited, its actual development may be affected by how a person uses his or her eyes. Individuals who spend considerable time reading, working at a computer, or doing other intense close visual work may be more likely to develop myopia.
Generally, myopia first occurs in school-age children. Because the eye continues to grow during childhood, it typically progresses until about age 20. However, myopia may also develop in adults due to visual stress or health conditions such as diabetes.
Myopia may also occur due to environmental factors or other health problems:
Some people may experience blurred distance vision only at night. With "night myopia," low light makes it difficult for the eyes to focus properly. Or the increased pupil size during dark conditions allows more peripheral, unfocused light rays to enter the eye.
People who do an excessive amount of near-vision work may experience a false or "pseudo" myopia. Their blurred distance vision is caused by overuse of the eyes' focusing mechanism. After long periods of near work, their eyes are unable to refocus to see clearly in the distance. Clear distance vision usually returns after resting the eyes. However, constant visual stress may lead to a permanent reduction in distance vision over time.
Symptoms of myopia may also be a sign of variations in blood sugar levels in people with diabetes or may be an early indication of a developing cataract.
A doctor of optometry can determine the cause of the
Inability to see the distant objects clearly, but the nearby objects are properly visible. This defect is known as nearsightedness or myopia and comes due to malnutrition, or the inability of the ciliary muscle to relax completely. This defect can also be corrected by using spectacles with lenses of desired characteristics.
Inability to see the nearby objects (at 25 cm from the eyes) clearly understand objects are properly visible. This defect is known as farsightedness or hypermetropia and comes due to weakening of ciliary muscles of the eye, at old age or a poor life style. It can be corrected by using spectacles with lens of desired characteristics.
Usually at an old age, an eye fluid gradually gets deposited on the eye lens the transparency of the eye lens. The defect is commonly known as cataract. A person suffering with cataract disease blood images of all objects around him or her. Cataract can be cured surgically.