Hyperopia
From Wikipedia, the free encyclopedia
| ICD-10 | H52.0 |
|---|---|
| ICD-9 | 367.0 |
Hyperopia, also known as hypermetropia or colloquially as farsightedness or longsightedness, 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 hypermetropia, the image will appear blurred.
People with hyperopia can experience blurred vision, asthenopia, accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus.<ref name="AOA Hyperopia">American Optometric Association. Optometric Clinical Practice Guideline: Care of the patient with hyperopia. 1997.</ref>
Hyperopia is often confused with presbyopia <ref name="WebMD">"Eye Health: Presbyopia and Your Eyes." WebMD.com. October, 2005. Accessed September 21, 2006.</ref><ref>Chou B. "Refractive Error and Presbyopia." Refractive Source.com Accessed September 20, 2006.</ref>, another condition that frequently causes blurry near vision. <ref name="AOA Presbyopia">American Optometric Association. Optometric Clinical Practice Guideline: Care of the patient with presbyopia. 1998.</ref> 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.<ref name="AOA Presbyopia"/> 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.<ref>Kazuo Tsubota, Brian S. Boxer Wacher, Dimitri T. Azar, and Douglas D. Koch, editors, , Hyperopia and Presbyopia, New York: Marcel Decker, 2003</ref>
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[edit] Classification of hyperopia
Hyperopia is typically classified according to its clinical appearance, its severity, or how it relates to the eye's accommodative status.<ref name="AOA Hyperopia"/>
[edit] Classification by clinical appearance
[edit] Classification by severity
Hyperopia is often categorized by the amount of refractive error:<ref>Augsburger AR. "Hyperopia." In: Amos JF, ed. Diagnosis and management in vision care. Boston: Butterworths, 1987:1010-19.</ref>
- Low hyperopia is a refractive error of +2.00 diopters (D) or less.
- Moderate hyperopia is a refractive error from +2.25 to +5.00 D.
- High hyperopia is a refractive error of +5.25 D or more.
[edit] Classification by accommodative status
[edit] Prevalence
An American study published in Archives of Ophthalmology found that more than 1 in 8 (12.8%) children between the ages of 5 and 17 have hyperopia,<ref>Kleinstein RN, Jones LA, Hullett S, Kwon S, Lee RJ, Friedman NE, Manny RE, Mutti DO, Yu JA, Zadnik K; Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error Study Group. "Refractive Error and Ethnicity in Children". Arch Ophthalmol. 2003 Aug;121(8):1141-7. PMID 12912692.</ref> and a recent Polish study found that 1 in 5 (21%) students between the age of 6 and 18 was hyperopic.<ref>Czepita D, Goslawski W, Mojsa A. "[Occurrence of hyperopia among students ranging from 6 to 18 years of age]." Klin Oczna. 2005;107(1-3):96-9. PMID 16052814.</ref> A recent Australian study found that nearly 4 in 10 (38.4%) children between the ages of 4 and 12 were hyperopic.<ref>Junghans BM, Crewther SG. "Little evidence for an epidemic of myopia in Australian primary school children over the last 30 years." BMC Ophthalmol. 2005 Feb 11;5(1):1. PMID 15705207</ref> A recent Brazilian study, however, found that nearly 7 in 10 (71%) of the students in one city were hyperopic.<ref>Garcia CA, Orefice F, Nobre GF, Souza Dde B, Rocha ML, Vianna RN. "[Prevalence of refractive errors in students in Northeastern Brazil. ]" Arq Bras Oftalmol. 2005 May-Jun;68(3):321-5. Epub 2005 Jul 26. PMID 16059562</ref> A study of Jordanian adults aged 17 to 40 found only 1 in 20 (5.7%) were hyperopic.<ref>Mallen EA, Gammoh Y, Al-Bdour M, Sayegh FN. "Refractive error and ocular biometry in Jordanian adults." Ophthalmic Physiol Opt. 2005 Jul;25(4):302-9. PMID 15953114.</ref> A recent study involving first-year undergraduate students in the United Kingdom found that 18.8% of British whites and 17.3% of British Asians were hyperopic.<ref>Logan NS, Davies LN, Mallen EA, Gilmartin B. "Ametropia and ocular biometry in a UK university student population." Optom Vis Sci. 2005 Apr;82(4):261-6. PMID 15829853.</ref>
[edit] Diagnosis
Visual acuity is affected according to the amount of hyperopia, as well as the patient's age, visual demands, and accommodative ability.<ref name="AOA Hyperopia"/>
[edit] Treatment
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.
[edit] Notes
<references/>
[edit] See also
cs:Dalekozrakost da:Langsynethed de:Weitsichtigkeit es:Hipermetropía fr:Hypermétropie it:Ipermetropia he:רוחק ראייה nl:Verziendheid ja:遠視 no:Hyperopi pl:Nadwzroczność pt:Hipermetropia sv:Översynthet tr:Hipermetropi zh:遠視
Categories: Eye | Optometry | Ophthalmology | Vision
