Wednesday, July 6, 2016

EXCIMER LASER Excimer Laser is a kind of laser used in the correction of myopia (nearsightedness), hyperopia (farsightedness) and astigmatism

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1. EXCIMER LASER Excimer Laser is a kind of laser used in the correction of myopia (nearsightedness), hyperopia (farsightedness) and astigmatism, all of which are called refractive disorders or lens disorders. Various applications of Excimer Laser exist depending on the patient and the type of eye disorder. It is applied on the central cornea in myopia, on the peripheral cornea in hyperopia, and to correct the axis of disorder in astigmatism. These applications are automatically set up under computer control.Preparations before Laser InterventionWe take the patient to the pre-op room and anesthetize his eyes with eye drops. We enter the patient information in the Excimer Laser computer. Then, we start the actual procedure by the machine itself. The eye and the eye area of the patient are cleansed and his head is covered with a sterile cloth. The operating physician cleans his hands with disinfectant solutions. Patient's eye is kept open throughout the operation by means of an instrument called blepharostat. There are three types of Excimer Laser to be used in correction of refractive disorders according to the application of the surgeon, and these methods differ in the preparation of the area to go under laser application:PRKThe thickest microscopic layer of cornea, stroma is sculpted. Laser is applied to reshape the cornea. Possible post-operation pain is to be reduced by use of contact lens on cornea after the procedure. LASIK LASIK method was invented for correction of all kinds of refractive disorders and does not require hospitalization. In LASIK, a special surgical blade called microkeratome is used to create a thin flap of the corneal surface, with a thickness of one third; and the flap is folded to one side. The untouched part holds this membrane in place. Excimer laser is delivered to reshape the distorted cornea, and the flap is returned to its original position without using any sticking material. LASIK has many advantages, which make it favorable among both patients and doctors: LASIK can correct mild to moderate levels of refractive errors as well as severe cases. It does not cause corneal scar or opacity. After LASIK, there is either no or a slight regress in vision. Patients will have stable vision results within a shorter period. There is only a slight pain after the procedure. Pain usually gives a stinging feel and can be relieved within 5 hours. Patients can have a great part of their improved vision on the following day after the surgery and go on with their daily activities within 24 hours. Patients may have both eyes treated at one session, and no patient attendant is needed. LASEK In LASEK, the corneal surface is loosened with alcohol for laser delivery and is lifted and folded aside. After laser deliver is completed, the folded epithelial flap is spread back in its place, and a soft contact lens is applied. Introduced as an alternative for PRK, LASEK is used for low degrees of disorder. Post-operational prognosis is the same as PRK whereas LASEK yields better clinical results. Custom laser procedure - WAVE FRONT A laser procedure conducted with pre-operative computerized measuring, WAVE FRONT is technology that makes possible the correction of severe aberrations in the eye. In PRK, LASIK and LASEK procedures conducted with Excimer Laser, the focus is on the correction of disorders by reshaping of cornea in front of the eye. However, the aberrations in the eye hinder the task of providing good sight, regardless of the degree of improvement in vision. WAVE FRONT technology allows for correction of these high order aberrations in the eye. Custom wave front mapping: In wave front mapping, patient's pupil is dilated, a beam of light is focused on retina of the eye and the beam is reflected as a diode laser beam. The reflected beam passes through the refractive media of the eye and leaves the eye through cornea. During the procedure, a plaque consisting of several small lenses detects optical characteristics of each region. Images at each lens section are recorded by a camera. A mathematical equation is applied on this raw data to obtain color-encoded a wave front map. Wave front analysis identifies all optical aberrations and overall refractive condition of the eye. It is possible to obtain data concerning not only retina, but also eye topography and the changes after a dilated pupil. Since cornea is the optical medium with the highest refractive power, the procedures to be performed only on this layer can help correction of aberrations up to 80%
                   
           

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