Lasik1- What does LASIK stand for?LASIK stands for Laser in situ keratomileusis 2- What does it mean?Use laser for ablation of the corneal bed under the corneal flap. It is non-reversible refractive surgery3- For what it is used?Lasik is used for correction of myopia, hyperopia and astigmatism. It is commonly used for myopia in which the surgeon will flatten the central part of the cornea. When it is used for hyperopia the surgeon will steepen the peripheral part of the cornea while for astigmatism the correction by laser will be done on part of the cornea that is corresponding to astigmatism axis4- What kind of laser in it?Excimer laser with high-energy ultra-violet radiation of a wavelength of 193nm this laser is called ArF-excimer.5- What is refractive error?Two major things in your eye will affect the refraction of lights into your macula. The first thing is cornea while the other thing is the lens. Two third of the refractive power of the eye comes from cornea while one third comes from the lens, so cornea plays a major rule in the refractive power of the eye.Emmetropia is the normal refractive power of the eye in which the reflected light will be focused on the macula, while ametropia is the condition in which the reflected light will not be focused on the macula and it can be myopia, hyperopia or astigmatismIn myopia the refractive power of the eye is strong so that the refracted light will be focus in front of the macula while in hyperopia the refractive power is weak leading to focusing of the refracted light behind the macula.Astigmatism is the condition in which the reflected lights do not focused in one point The shape of the cornea and its thickness play a major rule in the refractive power of the eye so the flatter the cornea the weaker is the refractive power leading to hyperopic shift of the eye, while the steeper the cornea like in keratoconus the stronger the power of the cornea leading to myopic shiftLasik will change the curvature of the cornea either to make it steeper or flatter so that the refracted light will focus on the macula6- How does lasik work?A thin corneal flap will be created using microkeratome. Under this flap there will the remaining of corneal tissue which is mostly consist of corneal stroma. With laser, there will be ablation of the corneal stroma to change the curvature of the cornea and so to change the refractive power of the cornea. The amount and the site where we will ablate the corneal stroma will depend on the type and the power of refractive error.After laser ablation the corneal flap will repositioned again to its place over the cornea without sutures7- What are the types of microkeratome?There are twp types of microkeratome. The first one is mechanical microkeratome which is a blade to cut the cornea. The second one which is called femtosecond laser, in which the doctor will use laser instead of mechanical blade for corneal flap creation. When lasik is done with the use of femtosecond laser, it will be called intralase lasik or bladeless lasik8- What is low and high order aberration?Low order aberrations are myopia, hyperopia and regular astigmatism in which they can be corrected by glasses. High order aberration is irregular astigmatism which can not be treated by glasses. Both aberrations will affect the final image received by the patient9- What are the causes of irregular astigmatism?Keratoconus, Corneal scar from trauma or infection, corneal grafts and refractive surgery10- What is the difference between conventional lasik and wavefront-guided lasik?Conventional lasik will treat low order aberration but in the same time it will increase the incidence of high order aberration. Wavefront guided lasik will treat low order and high order aberration and also decrease the chance of new high order aberrations11- How does wavefront analysis work?A beam of light is focused in the retina and this light is reflected back through the eye into a screen in which it will form a map. This map either will be in 3 dimensional shapes or 2 dimensional shapes. Your doctor will be able to know what low order and high order aberrations that you have and he can reshape your cornea according to the wavefront analysis map. Wavefront laser surgery can treat low order aberration and in the same time treat high order aberration or decrease the chance that the patient will have these aberrations after conventional lasik procedures. For more information about wavefront analysis click hereHistory of lasik To patient evaluation page To lasik procedure To lasik complications Lasik and dry eyes Lasik costs Learn how lasik can save you money
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