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Hyperopia, also known as hypermetropia or colloquially as farsightedness , is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short or when the lens cannot become round enough), causing inability to focus on near objects, and in extreme cases causing a sufferer to be unable to focus on objects at any distance. As an object moves towards the eye, the eye must increase its power to keep the image on the retina. If the power of the cornea and lens is insufficient, as in hyperopia, the image will appear blurred.
Hyperopia is often confused with presbyopia , another condition that frequently causes blurry near vision.  Presbyopes who report good far vision typically experience blurry near vision because of a reduced accommodative amplitude brought about by natural aging changes with the crystalline lens. It is also sometimes referred to as farsightedness, since in otherwise normally-sighted persons it makes it more difficult to focus on near objects than on far objects.
Classification of hyperopia
Classification by clinical appearance
- Simple hyperopia
- Pathological hyperopia
- Functional hyperopia
It also occurs when light entering the eye focuses behind the retina.
Various eye care professionals, including ophthalmologists, optometrists, and opticians, are involved in the treatment and management of hyperopia. At the conclusion of an eye examination, an eye doctor may provide the patient with an eyeglass prescription for corrective lenses.
Minor amounts of hyperopia are sometimes left uncorrected, however, larger amounts may be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
Hyperopia is sometimes correctable with various refractive surgery procedures.
- American Optometric Association. Optometric Clinical Practice Guideline: Care of the patient with hyperopia. 1997.
- "Eye Health: Presbyopia and Your Eyes." WebMD.com. October, 2005. Accessed September 21, 2006.
- Chou B. "Refractive Error and Presbyopia." Refractive Source.com Accessed September 20, 2006.
- American Optometric Association. Optometric Clinical Practice Guideline: Care of the patient with presbyopia. 1998.
- Kazuo Tsubota, Brian S. Boxer Wacher, Dimitri T. Azar, and Douglas D. Koch, editors, , Hyperopia and Presbyopia, New York: Marcel Decker, 2003
- pupilEyes - Learn how Hyperopia happens
- DocShop.com - Hyperopia Treatments
- Scottish Sensory Centre - Medical Info on Hypermetropia
Eye disease - pathology of the eye (H00-H59, 360-379)
lacrimal system: Dacryoadenitis - Epiphora - Dacryocystitis
orbit: Exophthalmos - Enophthalmos
|Optic nerve and visual pathways||
Optic neuritis - Papilledema - Optic atrophy - Leber's hereditary optic neuropathy - Dominant optic atrophy - Optic disc drusen - Glaucoma - Toxic and nutritional optic neuropathy - Anterior ischemic optic neuropathy
accommodation and refraction
Paralytic strabismus: Ophthalmoparesis - Progressive external ophthalmoplegia - Palsy (III, IV, VI) - Kearns-Sayre syndrome
Other strabismus: Esotropia/Exotropia - Hypertropia - Heterophoria (Esophoria, Exophoria) - Brown's syndrome - Duane syndrome
|Visual disturbances and blindness||
Amblyopia - Leber's congenital amaurosis - Subjective (Asthenopia, Hemeralopia, Photophobia, Scintillating scotoma) - Diplopia - Scotoma - Anopsia (Binasal hemianopsia, Bitemporal hemianopsia, Homonymous hemianopsia, Quadrantanopia) - Color blindness (Achromatopsia, Dichromacy, Monochromacy) - Nyctalopia (Oguchi disease) - Blindness/Low vision
Trachoma - Onchocerciasis
See also congenital
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