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

The Study of Myopia and Photorefractive KeratectomyMyopia is delimitate as improvidentness, which exists when the refractive elements of the mall (cornea and lens) place the image in presence of the retina. The ill-judged condition is common in infants but generally levels eat up to normal vision as the infant ages (Vander & Gault, 1998). Myopia occurs in virtually 25% of the adult U.S. population. Many adults use constituteive lenses or contacts to correct their unretentive vision to 20/20 vision (Drexler et al., 1998). Many peck find contacts or glasses hindering in their personal and/or professional lifestyle. For example, military pilots cannot wear glasses while flying and or so firemen may find glasses too dangerous to wear during a rescue attempt. There is refractive surgery available to correct myopic eyes, like Photorefractive Keratectomy (PRK). Why do people have myopia, what can be done to correct myopia, and what are the results of corrective surgical procedure s? These are a few questions that will be addressed and analyzed.For an eye to point right on an intention, it must be placed in a certain(a) position in front of the eye. The primary central tip is the point on the optical axis where an object can be placed for parallel rays to come from the lens. The vicarious 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 moved forward from infinity, in order to be focused on the retina. The far 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 which an object will be in foc us on the retina when the eye is accommodating. Thus, moving an object closer will cause the perception of the object to blur. The measurement of these refractive errors are in standard units called dioptres (D). A diopter is the reciprocal 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.