visual impairment essays

visual impairment essays " People catergorized as visually impaired range from individuals with mild visual losses to those with low vision to those who are totally blind" (Winzer,370). Vision impairments does not necessarily mean a total loss of sight. Some visually impaired person can detect light, others can see shapes and forms, and others can see nothing at all. Generally, many different problems that interfere the retina to form image or the transmission of retinal images to the brain can cause blindness or vision impairment. It can be heredity or caused by disease or damage after birth. In some cases a specific reason cannot be determined. There are four major types of vision impairments. The first type are refractive errors. It is cause by the change of shape or size of the eyeball, conera or the lens. Myopia (short-sighted) and hyperopia (long-sighted) are two common examples. People with myopia or hyperopia cannot focus image accurately on the retina. Another example is astigmatism, it is caused by the abnormal curve shape of the cornera or the lens. And it can cause distorted or blurred vision. The second type are ocular motor problems. It is caused by irregular movement of the ocular muscles that control the movement of the eyeballs. It leads to the inability for the eyes to control focusing objects. Strasbismus is an example. This condition effects about 2 percent (2 out of 100) of all young children. Strabismus is a lack of coordinated muscle movement or focusing ability between the eyes, causing the eyes to point in different directions. One or both eyes may turn inward (crossed eyes) or outward ("walleye"). The eyes, the brain area that controls vision, and the muscles attached to the eyeball are involved. It result in the child that looks in certain directions, double vision (sometimes), vision in one eye only, with loss of depth perception. Strabismus can affect both sexes, all ages, but it usually begins during ear ...