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

A Functioning center of attention (Emmetropia)The eye is the organ of sight. It is used in almost everything we do, from playing shimmer to reading. A normal and well functioning eye can concentre objects and images, both near and far, perceive depth and adapt to changes in unmortgaged. The recognition of depth is due to having two discontinue eyes creating two separate images, while the ability to adapt to ex angiotensin converting enzymerated change is attributed to the iris and the dilater muscles. However these two aspects of the eye are not involved in laser eye surgery and will not be discussed in reference. The centralizeing of objects and images is very much part of laser eye surgery. In order for a clear visual image to be create the image must come to a point on the retina. well-heeled rays do not normally travel toward each other, usually the unused rays either travel outwards or almost parallel, for this reason the escaped rays must be refracted. The cornea i s the primary place of refraction, the bent commence rays thence travel by dint of the aqueous humor and the pupil to the lens. Here the light is one 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 tiny pit in the middle of the macula). It is in this constituent 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, enough thinner to focus distant objects and fatter to focus near by objects. This process, of changing the lens thickness is known as accommodation. In order for this to come about the ciliary muscles contract and relax. The contraction fattens the lens and the relaxation stretches the lens. The eye functions on much the same pr inciple as a camera. The iris, or dyed 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) work on to focus light rays from the object viewed onto the retina at the back of the eye. The retina then transmits the " limn" of the object viewed to the brain 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 fewer days rather than weeks. 4) Less corneal scarring in the long term, slight change due to better (regression) and thus greater stability of the correction. When study only the benefits of Lasik over PRK the first impression is that Lasik has the authority to be a superior procedure. There is however, a very significant list of potential complications or risks and these include1) Failure of automated i nstrument to leave a hinge on the corneal quake, 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) First incision in like manner deep (perforation of the eye) or too shallow, causing a hole in the flap. 6) Invasion of the surface create from raw stuff 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 complex and finicky automated diamond-cutting devices. 10) The procedure is much to a greater extent dependent upon surgeons operating skills, than the computerized precision of the PRK procedure.