圓錐角膜Keratoconus

{{Infobox medical condition (new)

| name            = Keratoconus 

| image           = Keratoconus_eye.jpg 

| width           = 275px

| caption         = The "cone shaped cornea" that is characteristic of keratoconus 

| field           = [[ophthalmology]]

| synonyms        = 

| pronounce       =  

| symptoms        = [[blurry vision]], [[nearsightedness]], [[light sensitivity]]<ref name=NIH2016/>

| onset           = early adulthood<ref name=NIH2016/>

| duration        =

| causes          = unknown<ref name=NIH2016/>

| risks           = 

| diagnosis       = [[slit lamp]] exam<ref name=NIH2016/>

| differential    =

| prevention      =

| treatment       = [[glasses]], [[contacts]], [[surgery]]<ref name=NIH2016/>

| medication      =

| frequency       = ~1 in 2,000 people<ref name=NIH2016/>

| deaths          = 

}}

<!-- Definition and symptoms -->

’’’Keratoconus’’’ (’’’KC’’’, ’’’KCN’’’, ’’’KTCN’’’) is a disorder of the [[Human eye|eye]] which results in progressive thinning of the [[cornea]].<!-- <ref name=NIH2016/> --> This may result in [[blurry vision]], [[double vision]], [[nearsightedness]], [[astigmatism]], and [[light sensitivity]].<!-- <ref name=NIH2016/> --> Usually both eyes are affected.<ref name=NIH2016>{{cite web|title=Facts About the Cornea and Corneal Disease|url=https://nei.nih.gov/health/cornealdisease|website=NEI|accessdate=5 November 2016|date=May 2016}}</ref> In more severe cases a scarring or a [[Fleischer ring|circle]] may be seen within the cornea.<ref name=Mig2010/>

<!-- Cause and diagnosis -->

While the cause is unknown, it is believed to occur due to a combination of [[genetic]], environmental, and [[hormonal]] factors.<!-- <ref name=NIH2016/> --> About seven percent of those affected have a family history of the condition.<ref name=NIH2016/> Proposed environmental factors include rubbing the eyes and [[atopy|allergies]].<ref name=Mig2010/> The underlying mechanism involves changes of the cornea to a [[Cone (geometry)|cone shape]].<!-- <ref name=NIH2016/> --> Diagnosis is by examination with a [[slit lamp]].<ref name=NIH2016/>

<!-- Treatment -->

Initially the condition can typically be corrected with [[glasses]] or [[soft contact lenses]].<!-- <ref name=NIH2016/> --> As the disease worsens special contact lenses may be required.<!-- <ref name=NIH2016/> --> In most people the disease stabilizes after a few years without severe vision problems.<!-- <ref name=NIH2016/> --> In a small number of people scarring of the cornea occurs and a [[corneal transplantation]] is required.<ref name=NIH2016/>

<!-- Epidemiology and culture -->

Keratoconus affects about 1 in 2000 people.<ref name=NIH2016/><ref name=Mig2010>{{cite journal|first1=Miguel|last1=Romero-Jiménez|first2=Jacinto|last2=Santodomingo-Rubido|first3=James S.|last3=Wolffsohn|title=Keratoconus: a review|journal=Contact Lens & Anterior Eye: The Journal of the British Contact Lens Association|date=1 August 2010|issn=1476-5411|pages=157–166; quiz 205|volume=33|issue=4|pmid=20537579|doi=10.1016/j.clae.2010.04.006}}</ref> It occurs most commonly in late childhood to early adulthood.<ref name=NIH2016/> While it occurs in all populations it may be more frequent in certain [[ethnic group]]s such as those of Asian descent.<ref name=Mig2010/> The word is from the [[Greek language|Greek]] ’’kéras’’ meaning cornea and the [[Latin language|Latin]] ’’cōnus’’ meaning cone.<ref>{{cite web|url=http://dictionary.reference.com/browse/keratoconus|title=’’Keratoconus’’ Origin|publisher=’’[[dictionary.com]]’’|accessdate=2 November 2015}}</ref>

==References==

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