Eye Surgery

The cornea is a very important part of the eye that helps focus light to create an image on the retina. It works just like a lens of a camera. The bending and focusing of light is also known as refraction. Usually the shape of the cornea and the eye are not perfect and the image on the retina is out of focus or distorted. These problems in the focusing power of the eye are known  as refractive errors. There are three known types of refractive errors: myopia, hyperopia and astigmatism. Combinations of myopia and astigmatism or hyperopia and astigmatism are common. Glasses or contact lenses are designed to compensate for the eye's imperfections. Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery. LASIK surgery is one of the options to fix these imperfections. In LASIK surgery, precise and controlled removal of corneal tissue by a special laser reshapes the cornea to make it perfect for clear and better vision.

 Radial Keratotomy and Photorefractive Keratectomy are other refractive surgeries used to reshape the cornea. In Radial Keratotomy, a very thisn a shrp knife is used to cut slits in the cornea changing its shape. Photorefractive Keratectomy was the first surgical procedure used to reshape the cornea, by sculpting, using a laser. After few years, LASIK was developed. The same type of laser is used for LASIK and Photorefractive Keratectomy . Often the exact same laser is used for the two types of surgery. The major difference between the two surgeries is the way that the stroma, the middle layer of the cornea, is exposed before it is vaporized with the laser. In Photorefractive Keratectomy , the top layer of the cornea, called the epithelium, is scraped away to expose the stromal layer underneath. In LASIK, a flap is cut in the stromal layer and the flap is folded back.

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