Clarity
| Classification according to ICD-10 | |
|---|---|
| H52.0 | Hypermetropia |
| ICD-10 online (WHO version 2019) | |
In the general language hyperopia said hyperopia ( Synonym: hyperopia or hyperopia ) is a so-called axial refractive error of the eye ( ametropia ), in which the eyeball relative to the refractive power of its optical device, the refractive power is too short or too low. This leads to the fact that the image position for optically infinitely distant objects is not in the retinal plane when the eye is relaxed (not accommodated ), and thus an essential prerequisite for a sharp visual impression is not fulfilled. Instead, the (virtual) image point lies behind the retina in the far-sighted eye, so that a blurred visual impression is created. The closer an object is brought to the eye, the further the image point shifts backwards. The result is an aberration that makes close objects appear more blurred than distant objects - the person affected sees better in the distance (hence the term "far-sighted" ) than in the vicinity. The extent of farsightedness is determined by means of a refraction and is given in diopters .
The hyperopia is mainly genetic. While numerous forms of congenital malformations of the eyeball are associated with hyperopia, hyperopia alone is not a disease, but a variant of normal eye development.
Hyperopia, accommodation and presbyopia
Low or moderate farsightedness is usually compensated involuntarily by increasing the refractive power of the eye lens ( accommodation ) so that it is initially not noticed by the affected person. As long as it is possible to see distant and near without symptoms, hyperopia does not need to be corrected. In children, hyperopia is part of the developmental process. As a rule, it is reduced in the course of growth (see graphic). Higher-grade hyperopia over three dioptres should, however, be corrected - at least partially - even in childhood, as otherwise there may be a risk of strabismus .
However, the ability to accommodate decreases with increasing age and, depending on the degree of hyperopia, usually reaches a value between the ages of 35 and 45 that is no longer sufficient for sharp vision, initially in the vicinity and later also in the distance. These physiological presbyopia (presbyopia) do so sooner noticeable than in people without hyperopia. If problems occur in the vicinity due to the deteriorating accommodation capacity of the lens, the correction of the hyperopia initially improves the near vision, but also a general relief of the accommodation - also when looking into the distance. Later, when the presbyopia continues to increase, additional close-up correction is required.
Treatment options
The convex glasses or contact lenses required to correct the hyperopia have a positive refractive index and a “+” sign in front of the power specification in dpt. Farsightedness can therefore be corrected with plus diopters. In recent years, treatment by surgical intervention using refractive surgery has also become possible for adults .
Even undercorrected hyperopia can lead to internal squint in childhood due to the accommodation required for compensation . An important part of the therapy is therefore an optimal correction of the glasses. This is done less to improve visual acuity than to reduce the tendency towards strabismus. It is not uncommon for such prescribed glasses not to produce a significant subjective improvement in visual acuity. However, this does not change the need to wear the prescribed correction anyway. Severe hyperopia in childhood should be corrected with attenuated lenses as a precaution , even with normal binocular vision and sufficient accommodation latitude , at the latest when the visual stress increases with school enrollment.
Before the invention of the intraocular lens, surgical removal of the eye lens without replacement in the case of lens opacities ( cataracts ), which was common before the invention of the intraocular lens , leads to hyperopia of around 13 dioptres and made cataract glasses necessary at that time .
etymology
The medical terms hyperopia and hypermetropia are derived from the ancient Greek ὑπέρ hypér “over” (or ὑπέρμετρος hypérmetros “excessive”) and ὤψ ōps “eye”. Presbyopia also comes from the Greek: πρεσβύτης presbýtis "old man" and "eye" (as above).
See also
literature
- GREHN, Franz: Ophthalmology . 30th edition, Springer, Berlin , 2008. ISBN 978-3-540-75264-6 .
- ROSENSTIEL, L. and THISSEN, B .: About the age-dependent refraction process in hyperopic children . In: Assembly of the Association of Rheinisch-Westfälischer Augenärzte. Meeting report 125, 1973, ZDB -ID 402742-5 , p. 50 ff.
Web links
Individual evidence
- ↑ Willibald Pschyrembel (founder), Christoph Zink (editor): Clinical dictionary with clinical syndromes and nouns Anatomica. 255th edition. Walter de Gruyter, Berlin 1986. ISBN 3-11-007916-X
- ^ Wilhelm Gemoll : Greek-German school and hand dictionary. 9th edition, reviewed and expanded by Karl Vretska . Freytag et al., Munich et al. 1965.
- ↑ Heinz F Wendt: Langenscheidts pocket dictionary of the modern Greek and German language. Langenscheidt, Berlin etc., 17th edition 1990. ISBN 3-468-10210-0
