There are different vision problems… Read the article, know about it and know how to cure it.
Hello! There are 3 common vision problems. They are listed below. Read it to know about it and how to cure it.
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Myopia is also know as near-sightness. A person with myopia can see nearby objects but cannot see the distant objects distinctly. A person with this edefect has the far point nearer than infinity. Such a person may see clearly upto a distance of a few meters. In a myopic eye, the image of the distant object is formed infront of the rectina but not in the rectina itself. This defect may arise due to (1) excessive curvature of the eye lens or (2) Elongation of the eyeball. This defect can be corrected by using a conacve lens of suitable power. The concave lens with suitable power will bring back the the image to the rectina.
Hypermetropia is also known as far-sightness. A person with hypermetropia can see distant objects clearly but cannot see nearby objects distinctly. The near point, for a person, is farther away from the normal near point (25cm). Such a person has to keep a reading meterial much beyond 25cm from the eye for a comfortable reading. This is because a light rays from a close-by objects are focussed at a point behind the rectina. This defect arises due to (1) the focal length of the eye lens is too long or (2) eyeball has become too small. This defect can be corrected by using a convex lens of appropriate power. Convex lens will add additional focussing and bring the image back to rectina.
The power of accommodation of the eye usually decreases with ageing. For most of the people, the near point gradually recedes away. They find it difficult to see the nearby abjects comfortably and distinctly without corrective eye lens. This defect is called presbyophia. It arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens. Sometimes, a person may suffer from both myopia and hypermetropia. Such person often require a bi-focal lenses. A common type of bi-focal lens have both concave and convex lens.The upper portion consist of a concave lens. It fasilitates distant vision. The lower portion consist of convex lens. It fasilitates near vision.
Okay! These are the different defects of vision and their correction. If you like my post please comment and add me as your friend… Keep reading all my post… thanks!