Subject: [xsl] Important, read this Jerry Katzman MD, more about monovision From: "paul.kholer paul.kholer" <paul.kholer@xxxxxxxxx> Date: Thu, 7 Feb 2008 12:17:50 +0200 |
What is LASIK? The eye and vision errors The parts of the eye. Indicated are the conjunctiva, sclera, choroid, optic nerve, retina, chamber angle, lens, cilary body, vitreous humor, aqueous humor, iris, pupil, cornea. The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. 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 (blurred) or distorted. These imperfections in the focusing power of the eye are called refractive errors. There are three primary types of refractive errors: myopia, hyperopia and astigmatism. Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects. Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects. Jerry Katzman MD Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. 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. In LASIK surgery, precise and controlled removal of corneal tissue by a special laser reshapes the cornea changing its focusing power. Precautions The safety and effectiveness of refractive procedures has not been determined in patients with some diseases. Discuss with your doctor if you have a history of any of the following: * Herpes simplex or Herpes zoster (shingles) involving the eye area. * Glaucoma, glaucoma suspect, or ocular hypertension. * Eye diseases, such as uveitis/iritis (inflammations of the eye) * Eye injuries or previous eye surgeries. * Keratoconus Other Risk Factors Your doctor should screen you for the following conditions or indicators of risk: * Blepharitis. Inflammation of the eyelids with crusting of the eyelashes, that may increase the risk of infection or inflammation of the cornea after LASIK. * Large pupils. Make sure this evaluation is done in a dark room. Although anyone may have large pupils, younger patients and patients on certain medications may be particularly prone to having large pupils under dim lighting conditions. This can cause symptoms such as glare, halos, starbursts, and ghost images (double vision) after surgery. In some patients these symptoms may be debilitating. For example, a patient may no longer be able to drive a car at night or in certain weather conditions, such as fog. * Thin Corneas. The cornea is the thin clear covering of the eye that is over the iris, the colored part of the eye. Most refractive procedures change the eye's focusing power by reshaping the cornea (for example, by removing tissue). Jerry Katzman MD Performing a refractive procedure on a cornea that is too thin may result in blinding complications. * Previous refractive surgery (e.g., RK, PRK, LASIK). Additional refractive surgery may not be recommended. The decision to have additional refractive surgery must be made in consultation with your doctor after careful consideration of your unique situation. For more information visit http://dr-jerry-katzman.com
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