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Refractive Errors

Your cornea is the clear front part of your eye. It is like a window that controls and focuses the light coming into the eye. If your cornea has an irregular shape, the light does not focus properly. Everything looks blurry. This is a refractive error.

Four common refractive errors are

Glasses or contact lenses can usually correct refractive errors. Laser eye surgery may also be a possibility.

National Eye Institute

Refraction Error on Wikipedia

'''Refraction error''' is an error in the focusing of light by the eye. There are two main types: spherical errors and cylindrical errors. These can be corrected by glasses,contact lenses, or refractive surgery. Spherical errors occur when the optics of the eye (the dioptrics) are either too powerful or too weak to focus light on the retina. It is as if the overall lens is more or less spherical than it needs to be. People with this refraction error see all contours as blurred. When the optics are too powerful for the length of the eyeball (this can arise from a cornea with too much curvature or an eyeball that is too long), one has myopia. When the optics are too weak for the length of the eyeball (this can arise from a cornea with not enough curvature or an eyeball that is too short), one has hyperopia. Cylindrical errors occur when the optics of the eye are too powerful or too weak across one meridian of the optics. It is as if the overall lens tends towards a cylindrical shape along that meridian. People with this refraction error see contours of a particular orientation as blurred, but see contours with orientations at right angles as clear. When one has a cylindrical error, one has astigmatism. Other refraction errors include keratoconus.

See also

* Eyeglass prescription *   [ Read More ]


External Resources

Vision Future - About various refractive errors and techniques for their treatment. (Nice, France) [French and Italian language pages also available]

Laser Eye Center of Lubbock - Clinic for advanced surgical correction of refractive errors.

Laser Eye Center of Lubbock - Clinic for advanced surgical correction of refractive errors.

Kentucky Eye Institute - Comprehensive eye care center with a full range of services including treatment for glaucoma, macular degeneration, diabetic retinopathy, cataracts, and refractive errors. Sixteen locations.



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