Far-sightedness(Redirected from Hyperopia)
Far-sightedness, also known as long-sightedness and hyperopia, is a condition of the eye in which light is focused behind, instead of on, the retina. This causes close objects to be blurry, while far objects may appear normal. As the condition worsens, objects at all distances may be blurred. Other symptoms may include headaches and eye strain. People with hyperopia can also experience accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus.
|Synonyms||Hypermetropia, hyperopia, longsightedness|
|Far-sightedness lens correction|
|Classification and external resources|
Correction is usually achieved by the use of convex corrective lenses. For near objects, the eye has to accommodate even more. Depending on the degree of hyperopia and the age of the person, which directly relates to the eye's accommodative ability, the symptoms can be different.
Far-sightedness primarily affects young children, with rates of 8% at 6 years and 1% at 15 years.
Signs and symptomsEdit
The signs and symptoms of far-sightedness are blurry vision, headaches, and eye strain. The common symptom is eye strain. Difficulty seeing with both eyes (binocular vision) may occur, as well as difficulty with depth perception.
As hyperopia is the result of the visual image being focused behind the retina, it has two main causes:
- Low converging power of eye lens because of weak action of ciliary muscles
- Abnormal shape of the cornea
Far-sightedness is often present from birth, but children have a very flexible eye lens, which helps to compensate. In rare instances hyperopia can be due to diabetes, and problems with the blood vessels in the retina.
In severe cases of hyperopia from birth, the brain has difficulty in merging the images that each individual eye sees. This is because the images the brain receives from each eye are always blurred. A child with severe hyperopia can never see objects in detail. If the brain never learns to see objects in detail, then there is a high chance of one eye becoming dominant. The result is that the brain will block the impulses of the non-dominant eye. In contrast, the child with myopia can see objects close to the eye in detail and does learn at an early age to see detail in objects.[medical citation needed]
Hyperopia is typically classified according to clinical appearance, its severity, or how it relates to the eye's accommodative status.
There are three clinical categories of hyperopia.
- Simple hyperopia
- Occurs naturally due to biological diversity.
- Pathological hyperopia
- Caused by disease, trauma, or abnormal development.
- Functional hyperopia
- Caused by paralysis that interferes eye's ability to accommodate.
There are also three categories severity:
- Refractive error less than or equal to +2.00 diopters (D).
- Refractive error greater than +2.00 D up to +5.00 D.
- Refractive error greater than +5.00 D.
There are also surgical treatments for far-sightedness:
- Laser eye surgery to reshape the cornea, so that glasses or contact lenses are no longer needed.
- Refractive lens exchange (RLE)
- A variation of cataract surgery where the natural crystalline lens is replaced with an artificial intraocular lens; the difference is the existence of abnormal ocular anatomy which causes a high refractive error.
- Laser epithelial keratomileusis (LASEK)
- Resembles PRK, but uses alcohol to loosen the corneal surface.
- Lowth, Mary. "Long Sight (Hypermetropia)". Patient. Patient Platform Limited. Retrieved 2016-02-26.
- "Facts About Refractive Errors". National Eye Institute. October 2010. Retrieved 30 July 2016.
- Moore, Bruce D.; Augsburger, Arol R.; Ciner, Elise B.; Cockrell, David A.; Fern, Karen D.; Harb, Elise (2008). "Optometric Clinical Practice Guideline: Care of the Patient with Hyperopia" (PDF). American Optometric Association. pp. 2–3, 10–11.
- "Facts About Hyperopia". National Eye Institute. Retrieved 2016-02-26.
- Castagno, VD; Fassa, AG; Carret, ML; Vilela, MA; Meucci, RD (23 December 2014). "Hyperopia: a meta-analysis of prevalence and a review of associated factors among school-aged children.". BMC ophthalmology. 14: 163. PMC . PMID 25539893. doi:10.1186/1471-2415-14-163.
- "Normal, near-sightedness, and far-sightedness". MedlinePlus Medical Encyclopedia. Retrieved 2016-02-26.
- "Farsightedness". MedlinePlus Medical Encyclopedia. Retrieved 2016-02-26.
- "Slit-lamp exam". MedlinePlus Medical Encyclopedia. Retrieved 2016-02-26.
- Chou, Roger; Dana, Tracy; Bougatsos, Christina (2011-02-01). "Introduction". Screening for Visual Impairment in Children Ages 1-5 Years: Systematic Review to Update the 2004 U.S. Preventive Services Task Force Recommendation (Report). Evidence Syntheses. 81. Rockville, MD: Agency for Healthcare Research and Quality – via PubMed Health.
- "Farsightedness (Hyperopia): Treatments". PubMed Health. U. S. National Library of Medicine. Retrieved 2016-02-26.
- "Treating long-sightedness". NHS Choices. National Health Service. Archived from the original on 2016-03-05. Retrieved 2016-02-26.
- Settas, George; Settas, Clare; Minos, Evangelos; Yeung, Ian Yl (2012-01-01). "Photorefractive keratectomy (PRK) versus laser assisted in situ keratomileusis (LASIK) for hyperopia correction". Cochrane Database of Systematic Reviews. 6: CD007112. ISSN 1469-493X. PMID 22696365. doi:10.1002/14651858.CD007112.pub3. Lay summary – PubMed Health (2012-02-17).
- "Laser Eye Surgery". MedlinePlus. Retrieved 2016-02-26.
- Alió, Jorge L.; Grzybowski, Andrzej; Romaniuk, Dorota (2014-12-10). "Refractive lens exchange in modern practice: when and when not to do it?". Eye and Vision. 1: 10. ISSN 2326-0254. PMC . PMID 26605356. doi: .
- "Complications of long-sightedness". NHS Choices. National Health Service. 2014-07-09. Archived from the original on 2016-03-05. Retrieved 2016-02-26.
- "hyperopia". Online Etymology Dictionary. Douglas Harper.
- Kulp, Marjean Taylor; Ying, Gui-shuang; Huang, Jiayan; Maguire, Maureen; Quinn, Graham; Ciner, Elise B.; Cyert, Lynn A.; Orel-Bixler, Deborah A.; Moore, Bruce D. (2014-04-01). "Associations between Hyperopia and other Vision and Refractive Error Characteristics". Optometry and vision science: official publication of the American Academy of Optometry. 91 (4): 383–389. ISSN 1040-5488. PMC . PMID 24637486. doi:10.1097/OPX.0000000000000223.
- Wilson, Edward M.; Saunders, Richard; Rupal, Trivedi (2008-11-14). Pediatric Ophthalmology: Current Thought and A Practical Guide. Springer Science & Business Media. ISBN 978-3-540-68632-3 – via Google Books.
- "National Institutes of Health releases data from largest pediatric eye study". National Eye Institute. 2011-08-19. Retrieved 2016-02-26.