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High Refractive Error Lasik

contributed by: David Huang, MD, PhD All contributors: Brad H. Feldman, M.D. and David Huang, MD, PhD Assigned editor: Review: Assigned status Up to Date by Natalie Afshari, MD FACSon January 20, 2015. {| cellspacing="5" |-!align="right" |Lead Editors: |add |- !align="right" |Contributing Editors: |add |- |} Visit EyeSmart from the American Academy of Ophthalmology for a brief, patient-friendly summary of LASIK and alternative refractive procedures. Contents 1 Introduction 1.1 History of LASIK 1.2 LASIK Indications for the Correction of Myopia and Astigmatism 1.3 Preoperative Evaluation 1.4 Contraindications to LASIK 1.5 Flap Thickness 1.6 Surgical Technique 1.7 Postoperative Care 1.8 Outcomes of LASIK for Myopia and Astigmatism 2 LASIK Complications 2.1 Wavefront-Guided LASIK 2.2 Femtosecond LASIK 2.3 Conclusions 3 References Introduction[edit | edit source] LASIK (laser in situ keratomileusis) is a surgical procedure designed to correct refractive errors. LASIK involves creating a corneal flap using a microkeratome (Figure 1), reshaping the cornea using an excimer laser to remove tissue from the underlying stromal bed and then replacing the flap. History of LASIK[edit | edit source] LASIK evolved from a variety of techniques in refractive surgery. Keratomileusis, with both freeze and non-freeze techniques was used in the USA in the 1970s. This procedure was followed by automated lamellar keratoplasty (ALK), in which a microkeratome was used to create either a free cap or a hinged corneal flap. Tissue from the corneal bed was removed to alter the refractive error and the flap was replaced. Keratomileusis and ALK were relatively imprecise mechanical techniques. After the ophthalmic excimer laser was developed, it was used to reshape the cornea in a technique called photorefractive keratectomy ( PRK ). LASIK combines the technique of creating a hinged corneal flap from ALK with excimer laser ablation from PRK (Figure 2). Potential advantages of LASIK over PRK include earlier postoperative stabilization and faster improvement of visual acuity; less postoperative patient discomfort; shorter duration of postoperative medication use; and an easier enhancement procedure. LASIK Indications for the Correction of Myopia and Astigmatism[edit | edit source] LASIK is indicated for the correction of low, moderate, and high myopia with and without astigmatism. The specific dioptric limits depends on the specific laser system and the regulatory agency of each country. In the U.S.A. the approved indications can be found on the Food and Drug Admini

Lasik Alternative Top Articles Monovision Lasik PRK, LASEK, Epi-Lasik RLE Lens Exchange Lasik Groupon $1,500 Off Lasik The USAEyes.org website complies with the HONcode standard for trustworthy health information: verify here. High Correction With Lasik Really bad eyesight presents difficult challenges for vision correction surgery. By Glenn Hagele Lasik laser eye surgery may not be best for very high correction. Alternatives should be considered. As a (very) general rule, patients with more than about http://eyewiki.aao.org/LASIK_for_Myopia_and_Astigmatism%3A_Safety_and_Efficacy 10.00 diopters of myopia (nearsighted, shortsighted) vision or more than around 3.00 diopters of hyperopia (farsighted, longsighted) vision are significantly less likely to achieve uncorrected vision after conventional or custom wavefront Lasik or Bladeless Lasik that is equal to their corrected vision before surgery. To determine your refractive error, read your prescription. Patients with greater than about 6.00 diopters of needed correction are http://www.usaeyes.org/lasik/lasik-bad-vision.htm at a higher risk of corneal haze if PRK is selected. This elevated risk of corneal haze may be able to be reduced by the use of 500mg of vitamin C taken orally twice a day for one week before surgery and at least two weeks after surgery. Yes, plain old vitamin C. Another technique to reduce the probability of corneal haze is the application of Mitomycin C to the cornea during surgery. Mitomycin C is a strong medicine that is appropriate when needed, but probably should be avoided when possible. LASEK and Epi-Lasik are techniques developed to provide ablation on the surface of the cornea as in PRK, but with a lower risk of corneal haze. Available studies are inconclusive if this is actually the situation. For the greatest margin of safety, patients needing greater than 6.00 diopters of correction may want to consider Lasik instead of PRK, LASEK, or Epi-Lasik. Lasik has a very low incidence of corneal haze with higher corrections. Additionally, patients with astigmatism that is greater than half their sphere, or more than 2.00 diopters are less likely to achieve uncorrected visi

site created by Berney Design Residual refractive errors Residual refractive errors are the differences between the intended refractive correction and the actual refractive correction. Refractive surgeons generally aim for 20/20 vision (good vision without http://www.visionsurgeryrehab.org/residualreferr.html glasses or contacts). But since sculpting human eye tissue is a bit like sculpting Jell-O, many people don't wind up with perfect 20/20 vision. There are numerous types of residual refractive errors. Most people who do not achieve 20/20 vision after the first surgery have several options. They can wear glasses or contact lenses to correct the remaining high refractive refractive error, or they can choose to undergo additional surgery to correct the residual refractive error (provided their corneas have enough thickness to allow the removal of more tissue). Additional surgery usually comes with a risk level similar to the original surgery. Some people can achieve 20/20 vision on a high contrast eye chart but still have horrible high refractive error vision. If the area of correction placed on the eye is smaller than the pupil, one may experience glare, arcing, starbursts and/or halos (commonly called “GASH”). Others are left with a “bumpy cornea” (called “irregular astigmatism” and/or “higher order aberrations” (HOAs) that cause the light to scatter as it enters the cornea. When this happens, the patient will see multiple images with each eye. There is no reliable surgical fix for these problems at this time, although technology continues to advance. Since glasses and soft contact lenses usually cannot mask these problems, gas permeable rigid contact lenses (“RGPs”, aka “hard lenses”) are the only option for this group of patients. Fitting prosthetic RGPs after refractive surgery can be challenging (due to the changed curvature of the cornea) and not everyone is able to wear these lenses successfully. There are also other types of residual refractive errors. Please see the articles in this section for information about each type of visual/optical complications and their treatment and management. back to visual-optical complications back to handbook

 
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