Myopia Refractive Error
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> Eye Health Information > Refractive Errors > Facts About Myopia Facts About Myopia Myopia Defined What is myopia? Myopia, also known as nearsightedness, is a common type of refractive error where close objects appear clearly, but distant objects appear blurry. When you look at an object, light rays reflect off that object and pass through the cornea and the lens of the eye, which bend (or refract) the light and focus it on the retina at the back of the eye. If you have perfect vision, the rays focus directly on the surface of the retina. But in a myopic eye, the eyeball is usually too long from front to back. This causes light rays to focus at a point in front of the retina, rather than directly on its surface. This makes distant objects blurry. Myopia can also be the result of a cornea that is too curved for the length of the eyeball or a lens that is too thick. For some people, their myopia may be caused by a combination of problems in the cornea, lens, and length of the eyeball. What are the symptoms of myopia? If
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Farsightedness, Hyperopia, Myopia, Nearsightedness To use the sharing features on this refractive error measurement page, please enable JavaScript. On this page Basics Summary Start Here Latest News Diagnosis and Tests refractive errors of the human eye Prevention and Risk Factors Treatments and Therapies Learn More Related Issues Specifics Genetics See, Play and Learn Images Research Statistics and Research Clinical Trials Journal Articles Resources https://nei.nih.gov/health/errors/myopia Reference Desk Find an Expert For You Children Patient Handouts Summary The cornea and lens of your eye helps you focus. Refractive errors are vision problems that happen when the shape of the eye keeps you from focusing well. The cause could be the length of the eyeball (longer or shorter), changes in the https://medlineplus.gov/refractiveerrors.html shape of the cornea, or aging of the lens. Four common refractive errors are Myopia, or nearsightedness - clear vision close up but blurry in the distance Hyperopia, or farsightedness - clear vision in the distance but blurry close up Presbyopia - inability to focus close up as a result of aging Astigmatism - focus problems caused by the cornea The most common symptom is blurred vision. Other symptoms may include double vision, haziness, glare or halos around bright lights, squinting, headaches, or eye strain. Glasses or contact lenses can usually correct refractive errors. Laser eye surgery may also be a possibility. NIH: National Eye Institute Start Here Facts about Astigmatism (National Eye Institute) Also in Spanish Facts about Hyperopia (National Eye Institute) Also in Spanish Facts about Myopia (National Eye Institute) Also in Spanish Facts about Presbyopia (National Eye Institute) Facts about Refractive Errors (National Eye Institute) Also in Spanish Refractive Errors (American Association for Pediatric Ophthalmology and Strabismus
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Instructions Laser Vision Correction LASIK Technology LASIK Testimonials Online Appointment LASIK Downloads Corneal surgery handbook LASIK Follow-Up Form LASIK@SN Back to LASIK Main Page LASIK CORNER What is Refractive Error? Normally, the rays of light entering the eye are brought to a precise focus on the retina – the light sensitive layer lining the back of the eye. When such a focus is not achieved, a refractive error results and vision is not clear. These imperfections in the focusing power of the eye are called refractive errors. The common refractive errors are: Myopia, or Nearsightedness; Hyperopia, or Farsightedness; Astigmatism Myopia: A myopic eye is longer than normal or has a cornea that is too steep, as a result of which the light rays focus in front of the retina. Close objects look clear, but distant objects appear blurred. Hyperopia (Farsightedness): Hyperopia is a term used to describe the condition of farsightedness. The causes of hyperopia are typically genetic and involve an eye that is too short or a cornea that is too flat, as a result of which images focus at a point behind the Retina. People with hyperopia can usually see distant objects well, but have trouble focussing on nearby objects Astigmatism (Distorted vision): courtesy : Allergan ; Eye Calender ASTIGMATISM (cylindrical error) occurs when the incoming light rays are unable to reach a common focus within the eye. Astigmatism distorts or blurs vision for both near and far objects. The cornea is the clear front window of the eye. A normal cornea is round and smooth, like a basketball. When you have astigmatism, the cornea curves more in one direction than in the other, like a football. It is possible to have astigmatism in combination with myopia or hyperopia. Our Websites Support Sankara Nethralaya Home Ophthalmic Links SN Kolkata SN Omtrust About Us LASIK International Patient Services Omlog Patient Care Feed Back Vision & Mission Statement The Sankara Nethralaya Academy Education Career P