High Refractive Error Myopia
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Vision Research & Ophthalmology (DIVRO) Student Training Programs NEI Home About NEI Health Information News and Events Grants and Funding Research at NEI Education Programs Training and Jobs Home > 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 myopia treatment 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 you have myopia, you have trouble seeing things far away, but you can see nearby things clearly. This is why myopia is commonly called nearsightedness. If you can see well enough to read what’s on your laptop or in a book, but you struggle to see what’s on the television or a movie screen, you may be nearsighted. Sometimes people with undiagnosed myopia will have headaches and eyestrain from struggling to clearly see things in the distance. Why does the eyeball grow too long? What causes the eyeball to grow too long isn’t complet
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Grants and Funding All Grants and Funding Division of Extramural Activities Division of Extramural Science high myopia treatment Programs Funding Opportunity Announcements Funding Mechanisms Supported by the NEI Research at NEI All Research at NEI Office of the Scientific myopia symptoms Director Office of the Clinical Director Education Programs All Education National Eye Health Education Program Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education Program Spanish-language Education Program (¡Ojo con su visión!) Vision and https://nei.nih.gov/health/errors/myopia Aging Program Training and Jobs All Training and Jobs NEI Summer Intern Program Diversity In Vision Research & Ophthalmology (DIVRO) Student Training Programs NEI Home About NEI Health Information News and Events Grants and Funding Research at NEI Education Programs Training and Jobs Home > Eye Health Information > Refractive Errors > Facts About Refractive Errors Facts About Refractive Errors This information was developed by the National https://nei.nih.gov/health/errors/errors Eye Institute to help patients and their families search for general information about refractive errors. An eye care professional who has examined the patient’s eyes and is familiar with his or her medical history is the best person to answer specific questions. Refractive Errors Defined What are refractive errors? Refractive errors occur when the shape of the eye prevents light from focusing directly on the retina. The length of the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens can cause refractive errors. What is refraction? Refraction is the bending of light as it passes through one object to another. Vision occurs when light rays are bent (refracted) as they pass through the cornea and the lens. The light is then focused on the retina. The retina converts the light-rays into messages that are sent through the optic nerve to the brain. The brain interprets these messages into the images we see. Frequently Asked Questions about Refractive Errors What are the different types of refractive errors? The most common types of refractive errors are myopia, hyperopia, presbyopia, and astigmatism. Myopia (nearsightedness) is a condition where objects up close appear clearly, while objects far away appear blurry. With myopia, light comes to focus in front of the retina instead of on the retina. Hyperopia (farsightedness) i
slideshowsWatch and learn about your health Symptom CheckerHelp diagnose common conditions MyHealthCheck and improve your health Clinical TrialsApply for a trial near http://patient.info/doctor/refraction-and-refractive-errors you Decision AidsHelp choosing the right treatmentMedicines Search health information A B C D E F G H I J K L M N O P Q R S T U V W X Y https://en.wikipedia.org/wiki/Refractive_error ZProfessional Reference Search professional reference A B C D E F G H I J K L M N O P Q R S T U V W X Y ZBrowse clinical guidelines PatientPro refractive error CompleteCreate a reflective diary, track the pages you read and get ads free experience Medical Calculators Articles for medical students New leaflets and updates Decision AidsForumsDirectoryBlogsPatient Access Sign in RegisterWelcome to PatientRegisterPatient AccessPatient- MyHealth- Forums- PatientPro|Sign inPatient AccessPatient- MyHealth- Forums- PatientProMyHealth | Blogs | Shop | Symptom checker Search Patient Home Professional Reference Refraction and Refractive ErrorsRefraction and Refractive Errors 963 Users are discussing this topic Article Related Support high refractive error Discuss Print PDF Email Bookmark Bookmarked Remove? CancelYou must be signed in to bookmark pagesView All NotesCancelYou must be signed into your pro account to make notes Listen On this pageOverviewRefractive errorsAssessment of refractive errorsManagement of refractive errorsPreventionAccommodative problemsReferencesPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.963 See also: Long Sight (Hypermetropia) written for patientsOverviewThe purpose of the globe is to receive light from the outside world and transmit it to the brain for processing. There are two aspects to this function. In the first instance, the light rays have to be correctly focused on to the back of the eye. Then, this information has to be converted to electrochemical signals by the cells within the retina and transmitted to the brain.In optical physics, the term 'refraction' is used to describe the bending of light rays as they pass across a particular medium. Refraction - whether by natural eye tissue or of an artificial lens - is measured in dioptres (D) which describes the power that a structure has to focus parallel rays of light. The higher
367.0-367.2-367.9 DiseasesDB 29645 MeSH D012030 [edit on Wikidata] Refractive error, also known as refraction error, is a problem with focusing of light on the retina due to the shape of the eye.[1] The most common types of refractive error are near-sightedness, far-sightedness, astigmatism, and presbyopia. Near-sightedness results in far objects being blurry, far-sightedness result in close objects being blurry, astigmatism causes objects to appear stretched out or blurry, and presbyopia results in a poor ability to focus on close objects. Other symptoms may include double vision, headaches, and eye strain.[1] Near-sightedness is due to the length of the eyeball being too long, far-sightedness the eyeball too short, astigmatism the cornea being the wrong shape, and presbyopia aging of the lens of the eye such that it cannot change shape sufficiently. Some refractive errors are inherited from a person's parents. Diagnosis is by eye examination.[1] Refractive errors are corrected with eyeglasses, contact lenses, or surgery. Eyeglasses are the easiest and safest method of correction. Contact lenses can provide a wider field of vision; however are associated with a risk of infection. Refractive surgery permanently changes the shape of the cornea.[1] The number of people globally with refractive errors has been estimated at one to two billion. Rates vary between regions of the world with about 25% of Europeans and 80% of Asians affected.[2] Near-sightedness is the most common disorder.[3] Rates among adults are between 15-49% while rates among children are between 1.2-42%.[4] Far-sightedness more commonly affects young child and the elderly.[5][6] Presbyopia affects most people over the age of 35.[1] The number of people with refractive errors that have not been corrected was estimated at 660 million (10 per 100 people) in 2013.[7] Of these 9.5 million were blind due to the refractive error.[7] It is one of the most common causes of vision loss along with cataracts, macular degeneration, and vitamin A deficiency.[8] Contents 1 Classification 2 Risk factors 2.1 Genetics 2.2 Environmental 3 Diagnosis 4 Management 5 Epidemiology 6 References 7 External links Classification[edit] An eye that has no refractive error when viewing distant objects is said to have emmetropia or be emmetropic meaning the eye is in a state in which it can focus parallel rays of light (light from distant objects) on the retina, without using any accommodation. A distant object in this case is defined as an object 8 meters or further away from the eye. An eye that has refractive error when viewing distant objects is said t