Editing Amblyopia (section)

{{short description|Failure of the brain to process input from one eye}}
{{Use dmy dates|date=June 2024}}
{{Infobox medical condition (new)
| name            = Amblyopia
| synonyms        = Lazy eye<ref name=NEI2013/>
| image           = Child eyepatch.jpg
| caption         = A child wearing an adhesive eyepatch to correct amblyopia
| field           = [[Ophthalmology]], [[optometry]]
| pronounce       = {{IPAc-en|ˌ|æ|m|b|l|i|ˈ|oʊ|p|i|.|ə}} {{respell|AM|blee|OH|pee|ə}}
| symptoms        = [[Decreased vision]]
| complications   =
| onset           = Before age five<ref name=BMJ2015/>
| duration        =
| types           =
| causes          = [[strabismus|Poor alignment of the eyes]], eye [[astigmatism|being irregularly shaped such that focusing is difficult]], one eye [[anisometropia|being more nearsighted or farsighted]], [[cataract|clouding of the lens]]<ref name=NEI2013/>
| risks           =
| diagnosis       = [[eye examination|Vision testing]]<ref name=NEI2013/>
| differential    = [[Brainstem]] disorders, [[optic nerve]] disorder, [[eye disease]]s<ref>{{cite book |last1=Ferri |first1=Fred F. | name-list-style = vanc | title = Ferri's differential diagnosis: a practical guide to the differential diagnosis of symptoms, signs, and clinical disorders |date=2010 |publisher=Elsevier/Mosby |location=Philadelphia, PA |isbn=978-0-323-07699-9 |page=Chapter A |edition=2nd}}</ref>
|prevention      =
|treatment       = [[Glasses]], [[eyepatch]]<ref name=NEI2013/><ref name=BMJ2015/><ref name=Mac2015/>
| medication      =
| prognosis       =
| frequency       = ~2% of adults<ref name=Web2005/>
| deaths          =
}}
<!-- Definition and symptoms -->
'''Amblyopia''', also called '''lazy eye''', is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye.<ref name=NEI2013/><!-- Quote = It develops when there's a breakdown in the way the brain and the eye work together, and the brain cannot recognize the sight from one eye. Over time, the brain relies more and more on the other, stronger eye  --> It results in decreased vision in an eye that typically appears normal in other aspects.<ref name=NEI2013/> Amblyopia is the most common cause of decreased vision in a single eye among children and younger adults.<ref name=NEI2013>{{cite web |title=Facts About Amblyopia |url=https://nei.nih.gov/health/amblyopia/amblyopia_guide |website=National Eye Institute |access-date=27 July 2016 |date=September 2013 |url-status = live |archive-url=https://web.archive.org/web/20160727233820/https://nei.nih.gov/health/amblyopia/amblyopia_guide |archive-date=27 July 2016}}</ref>

<!-- Cause and diagnosis -->
The cause of amblyopia can be any condition that interferes with focusing during early childhood.<ref name=NEI2013/><ref name=Sch2002>{{cite book |last1=Schwartz |first1=M. William | name-list-style = vanc |title=The 5-minute pediatric consult |date=2002 |publisher=Lippincott Williams & Wilkins |location=Philadelphia |isbn=978-0-7817-3539-1 |page=110 |edition=3rd |url=https://books.google.com/books?id=SRi0WnNisW8C&pg=PA110 }}</ref> This can occur from [[strabismus|poor alignment of the eyes]] (strabismic), an eye [[astigmatism|being irregularly shaped]] such that focusing is difficult, one eye [[anisometropia|being more nearsighted or farsighted]] than the other (refractive), or [[cataract|clouding of the lens]] of an eye (deprivational).<ref name=NEI2013/> After the underlying cause is addressed, vision is not restored right away, as the mechanism also involves the brain.<ref name=Sch2002/><ref name=Levi2013>{{cite journal |vauthors = Levi DM |title = Linking assumptions in amblyopia |journal = Visual Neuroscience |volume = 30 |issue = 5–6 |pages = 277–87|date = November 2013 |pmid = 23879956 |pmc = 5533593 |doi = 10.1017/S0952523813000023 }}</ref> Amblyopia can be difficult to detect, so [[eye examination|vision testing]] is recommended for all children around the ages of four to five.<ref name=BMJ2015>{{cite journal |vauthors = Jefferis JM, Connor AJ, Clarke MP |title = Amblyopia |journal = BMJ |volume = 351 |pages = h5811 |date = November 2015 |pmid = 26563241 |doi = 10.1136/bmj.h5811 |s2cid = 220101666}}</ref>

<!-- Treatment and prognosis -->
Early detection improves treatment success.<ref name=BMJ2015/> [[Eye glasses|Glasses]] may be all the treatment needed for some children.<ref name=BMJ2015/><ref name=Mac2015>{{cite journal |vauthors = Maconachie GD, Gottlob I |title = The challenges of amblyopia treatment |journal = Biomedical Journal |volume = 38 |issue = 6 | pages = 510–6 | date = December 2015 |pmid = 27013450 |pmc = 6138377 |doi = 10.1016/j.bj.2015.06.001 }}</ref> If this is not sufficient, treatments which encourage or force the child to use the weaker eye are used.<ref name=NEI2013/> This is done by either using a [[eyepatch|patch]] or putting [[atropine]] in the stronger eye.<ref name=NEI2013/><ref name="National Eye Institute 2019">{{cite web |title=Amblyopia (Lazy Eye) |website=National Eye Institute |date=2019-07-02 |url=https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/amblyopia-lazy-eye |access-date=2020-01-31 |quote=Putting special eye drops in the stronger eye. A once-a-day drop of the drug atropine can temporarily blur near vision, which forces the brain to use the other eye. For some kids, this treatment works as well as an eye patch, and some parents find it easier to use (for example, because young children may try to pull off eye patches).}}</ref> Without treatment, amblyopia typically persists.<ref name=NEI2013/> Treatment in adulthood is usually much less effective.<ref name=NEI2013/>

<!-- Epidemiology and prognosis -->
Amblyopia begins by the age of five.<ref name=BMJ2015/> In adults, the disorder is estimated to affect 1–5% of the population.<ref name=Web2005>{{cite journal |vauthors = Webber AL, Wood J |title = Amblyopia: prevalence, natural history, functional effects and treatment |journal = Clinical & Experimental Optometry |volume = 88 |issue = 6 |pages = 365–75 |date = November 2005 |pmid = 16329744 |doi = 10.1111/j.1444-0938.2005.tb05102.x |s2cid = 39141527 |doi-access = free }}</ref> While treatment improves vision, it does not typically restore it to normal in the affected eye.<ref name=BMJ2015/> Amblyopia was first described in the 1600s.<ref name=Mar2016>{{cite book |veditors = Fazzi E, Bianchi PE |title=Visual Impairments and Developmental Disorders: From diagnosis to rehabilitation Mariani Foundation Paediatric Neurology |date=2016 |publisher=John Libbey Eurotext |isbn=978-2-7420-1482-8 |chapter-url=https://books.google.com/books?id=VVI2DAAAQBAJ&pg=PT26 |vauthors = Bianchi PE, Ricciardelli G, Bianchi A, Arbanini A, Fazzi E |chapter = Chapter 2: Visual Development in Childhood |url-status = live |archive-url=https://web.archive.org/web/20170908154722/https://books.google.com/books?id=VVI2DAAAQBAJ&pg=PT26|page=26 |archive-date=8 September 2017}}</ref> The condition may make people ineligible to be pilots or police officers.<ref name=BMJ2015/> The word ''amblyopia'' is from [[Ancient Greek|Greek]] ἀμβλύς ''amblys'', meaning "blunt", and ὤψ ''ōps'', meaning "sight".<ref>{{cite web |title=Online Etymology Dictionary |url= http://www.etymonline.com/index.php?term=amblyopia |website=etymonline.com |access-date=5 May 2017|url-status = live |archive-url=https://web.archive.org/web/20170908154722/http://www.etymonline.com/index.php?term=amblyopia |archive-date=8 September 2017}}</ref>