The Eye And Laser Eye Surgery Essay -- essays research papers

A Functioning Eye (Emmetropia)The shopping mall is the electric organ of sight. It is used in al some e very(prenominal)thing we do, from playing sport to reading. A convention and well functioning shopping centre can condense goals and images, both some and far, perceive depth and adapt to changes in get out. The perception of depth is collectible to having both separate eyes creating two separate images, while the major power to adapt to light change is attributed to the iris and the dilator muscles. However these two aspects of the eye are non involved in laser eye surgery and will not be discussed in reference. The focusing of objects and images is very much part of laser eye surgery. In order for a clear visual image to be formed the image must(prenominal) come to a point on the retina. Light rays do not normally impress toward each other, usually the light rays either travel outwards or almost parallel, for this reason the light rays must be refracted. The cornea is the primary place of refraction, the bent light rays then travel finished the aqueous snappishness and the pupil to the lens. Here the light is one once again refracted even closer together, the light then goes through the vitreous humor and is projected onto the retina. The focus of the lens should be aimed at the fovea centralis (a critical pit in the middle of the macula). It is in this region that vision is most sharp. For this reason, instead of simply staring at one point the eye must constantly scan the area to focus the whole object or image. In order to accommodate the changing distances of the object or image the lens in the eye has to adjust, becoming thinner to focus distant objects and fatter to focus near by objects. This process, of changing the lens ponderousness is known as accommodation. In order for this to occur the ciliary muscles bugger off and relax. The contraction fattens the lens and the relaxation stretches the lens. The eye functions on much th e alike(p) principle as a camera. The iris, or coloured portion of the eye, acts as a shutter to regulate the amount of light admitted to the eye. The cornea (the clear window at the front of the eye) and the lens (located behind the pupil) serve to focus light rays from the object viewed onto the retina at the back of the eye. The retina then transmits the "picture" of the object viewed to the foreland where the object is "seen". Clear vision is the result of light rays passing through the cornea,... ...ubstantially reduced. 3) Post-operative visual acuity is restored within a few days kinda than weeks. 4) Less corneal scarring in the long term, less change cod to healing (regression) and thus greater stability of the correction. When comparing only the benefits of Lasik all over PRK the first impression is that Lasik has the potential to be a superior procedure. in that location is however, a very significant list of potential complications or risks and the se hold1) Failure of automated instrument to leave a hinge on the corneal flap, with the first incision. 2) Loss of the corneal flap during the operation. 3) Loss of the corneal flap after the operation. 4) Slipping of the flap and healing off center. 5) outgrowth incision too deep (perforation of the eye) or too shallow, causing a hole in the flap. 6) Invasion of the surface waver into the central tissue of the cornea. 7) Infection of the cornea. 8) Loss of visual acuity - from scarring or from decentration of the PRK. 9) Technical problems with interlocking and finicky automated diamond-cutting devices. 10) The procedure is much more dependent upon surgeons direct skills, than the computerized precision of the PRK procedure.