The Study of Myopia and Photorefractive Keratectomy :: Eyes Vision Health Essays

The Study of Myopia and Photorefractive KeratectomyMyopia is defined as nearsightedness, which exists when the refractive elements of the eye (cornea and lens) place the image in front of the retina. The forgetful specify is common in infants but generally levels off to convening vision as the infant ages (Vander & Gault, 1998). Myopia occurs in about 25% of the adult U.S. population. Many adults use corrective lenses or contacts to correct their ill-considered vision to 20/20 vision (Drexler et al., 1998). Many people divulge contacts or glasses hindering in their personal and/or skipper lifestyle. For example, military pilots cannot wear glasses while flying and some firemen may find glasses too dangerous to wear during a carry through attempt. There is refractive surgery available to correct myopic eyes, exchangeable Photorefractive Keratectomy (PRK). Why do people have myopia, what can be through to correct myopia, and what are the results of corrective surgical procedur es? These are a a few(prenominal) questions that will be addressed and analyzed.For an eye to focus correctly on an inclination, it must be placed in a certain assign in front of the eye. The primary focal level is the point along the opthalmic axis where an object can be placed for reduplicate rays to come from the lens. The secondary focal point is the point along the optical axis where in coming parallel rays are brought into focus. The primary focal point has the objects image at infinity, where as the secondary focal point has the object at infinity. For people who have myopic eyes, the secondary focal point is anterior to the retina in the vitreous. Thus, the object must be locomote forward from infinity, in order to be focused on the retina. The farther point is determined by the objects distance where light rays focus on the retina while the eye is not accommodating. The far point in the myopic eye is between the cornea and infinity. The near point is determined by wh ich an object will be in focus on the retina when the eye is accommodating. Thus, moving an object closer will cause the perception of the object to blur. The quantity of these refractive errors are in standard units called diopters (D). A diopter is the interactional of a distance of the far point in meters (Vander & Gault, 1998). The myopic condition manipulates these variables in order to ultimately make a nearsighted individual.