High Refractive Error Definition
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Types Refractive Errors
Errors Refractive Errors Reviewed by Jill E. Bixler, M.D. On this page: What Is a Refractive Error? Symptoms refractive error treatment Causes Risk Factors Tests and Diagnosis Treatment and Drugs Clinic Information What Is a Refractive Error? Refractive error means that the shape of your eye does not bend light refractive error correction correctly, resulting in a blurred image. The main types of refractive errors are myopia (nearsightedness), hyperopia (farsightedness), presbyopia (loss of near vision with age), and astigmatism. Symptoms Blurred vision Difficulty reading or seeing up close Crossing of the eyes in children (esotropia) Causes Overuse of the eyes does not cause or worsen refractive error. The causes of the main types
Refractive Errors Pdf
of refractive error are described below: Myopia(close objects are clear, and distant objects are blurry) Also known as nearsightedness, myopia is usually inherited and often discovered in childhood. Myopia often progresses throughout the teenage years when the body is growing rapidly. Watch a video explaining myopia. Hyperopia (close objects are more blurry than distant objects) Also known as farsightedness, hyperopia can also be inherited. Children often have hyperopia, which may lessen in adulthood. In mild hyperopia, distance vision is clear while near vision is blurry. In more advanced hyperopia, vision can be blurred at all distances. Watch a video explaining hyperopia. Presbyopia (aging of the lens in the eye) After age 40, the lens of the eye becomes more rigid and does not flex as easily. As a result, the eye loses its focusing ability and it becomes more difficult to read at close range. This normal aging process of the lens can also be combined with myopia, hyperopia or astigmatism. Watch a video explaining presbyopia. Astigmatism Astigmatism usually occurs when the front surface of the
Care Sub-Section Eye Clinics Make an Appointment How to Find Us Eye Conditions Find a Doctor Navigation: Eye Conditions Eye Conditions Video Library FAQ "Ask the Expert" Ophthalmology Links Search the Kellogg website Navigation: Breadcrumbs Home refractive error in children Patient Care Eye Conditions Refractive Errors Refractive Errors Reviewed by Jill E. Bixler, refractive error ppt M.D. On this page: What Is a Refractive Error? Symptoms Causes Risk Factors Tests and Diagnosis Treatment and Drugs Clinic
Refractive Errors Of The Human Eye
Information What Is a Refractive Error? Refractive error means that the shape of your eye does not bend light correctly, resulting in a blurred image. The main types of refractive errors are myopia http://kellogg.umich.edu/patientcare/conditions/refractive.errors.html (nearsightedness), hyperopia (farsightedness), presbyopia (loss of near vision with age), and astigmatism. Symptoms Blurred vision Difficulty reading or seeing up close Crossing of the eyes in children (esotropia) Causes Overuse of the eyes does not cause or worsen refractive error. The causes of the main types of refractive error are described below: Myopia(close objects are clear, and distant objects are blurry) Also known as nearsightedness, myopia http://kellogg.umich.edu/patientcare/conditions/refractive.errors.html is usually inherited and often discovered in childhood. Myopia often progresses throughout the teenage years when the body is growing rapidly. Watch a video explaining myopia. Hyperopia (close objects are more blurry than distant objects) Also known as farsightedness, hyperopia can also be inherited. Children often have hyperopia, which may lessen in adulthood. In mild hyperopia, distance vision is clear while near vision is blurry. In more advanced hyperopia, vision can be blurred at all distances. Watch a video explaining hyperopia. Presbyopia (aging of the lens in the eye) After age 40, the lens of the eye becomes more rigid and does not flex as easily. As a result, the eye loses its focusing ability and it becomes more difficult to read at close range. This normal aging process of the lens can also be combined with myopia, hyperopia or astigmatism. Watch a video explaining presbyopia. Astigmatism Astigmatism usually occurs when the front surface of the eye, the cornea, has an asymmetric curvature. Normally the cornea is smooth and equally curved in all directions, and light entering the cornea is focused equally on all planes, or in all directions. In astigmatism, the front surface of the
中文 English Français Русский Español RSS Feed Youtube Twitter Facebook Google + iTunes Play Store What is a refractive error? Online Q&A 7 October 2013 Q: What is a refractive error? http://www.who.int/features/qa/45/en/ A: A refractive error is a very common eye disorder. It occurs when the eye cannot clearly focus the images from the outside world. The result of refractive errors is blurred vision, which http://patient.info/doctor/refraction-and-refractive-errors is sometimes so severe that it causes visual impairment. The four most common refractive errors are: myopia (nearsightedness): difficulty in seeing distant objects clearly; hyperopia (farsightedness): difficulty in seeing close objects clearly; refractive error astigmatism: distorted vision resulting from an irregularly curved cornea, the clear covering of the eyeball. presbyopia: which leads to difficulty in reading or seeing at arm's length, it is linked to ageing and occurs almost universally. Refractive errors cannot be prevented, but they can be diagnosed by an eye examination and treated with corrective glasses, contact lenses or refractive surgery. If corrected in time high refractive error and by eye-care professionals, they do not impede the full development of good visual function. Correction is provided in different forms according to the defect, the age f the person, the requirements in terms of work of activity performed. WHO estimates that 153 million people worldwide live with visual impairment due to uncorrected refractive errors. This figure does not include the people living with uncorrected presbyopia, which is likely to be quite significant, according to some early evidence. WHO, its Member States and partners are working to find ways to provide good quality, professionally prescribed, local, affordable corrective refraction services to people in need, especially in poor areas with limited eye care services. Related links Refractive errors and low vision Prevention of avoidable blindness and visual impairment Share Email Twitter Facebook Google Delicious LinkedIn More... Print Question and answer archives Submit a question You are here: Features Online Q&A Quick Links Sitemap Home Health topics Data Media centre Publications Countries Programmes and projects Governance About WHO Help and Services Contacts FAQs Employment Feedback Privacy E-mail scams WHO Regional Offices WHO African Region WHO Region of the Americas WHO South-East Asia Region
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