Title: Ectopia lentis

{{short description|Malposition of the lens of the eye}}
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| image           = Ectopia Lentis in Marfan syndrome.jpg
| caption         = Ectopia lentis in a patient with [[Marfan syndrome]]. [[Zonule of Zinn|Zonular fibers]] are visible.
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[[File:Luxating lens - anterior.JPG|thumb|Anterior lens luxation in a dog]]
[[File:Feline lens luxation 2.JPG|thumb|Anterior lens luxation with cataract formation in a cat]]

'''Ectopia lentis''' is a [[Ectopia (medicine)|displacement or malposition]] of the [[eye]]'s [[lens (anatomy)|lens]] from its normal location. A partial dislocation of a lens is termed '''lens subluxation''' or '''subluxated lens'''; a complete dislocation of a lens is termed '''lens luxation''' or '''luxated lens'''.

==Ectopia lentis in dogs and cats==
Although observed in humans and cats, ectopia lentis is most commonly seen in [[dog]]s. [[Zonule of Zinn|Ciliary zonules]] normally hold the lens in place. Abnormal development of these zonules can lead to primary ectopia lentis, usually a bilateral condition. Luxation can also be a secondary condition, caused by trauma, [[cataract]] formation (decrease in lens diameter may stretch and break the zonules), or [[glaucoma]] (enlargement of the globe stretches the zonules). Steroid administration weakens the zonules and can lead to luxation, as well. Lens luxation in cats can occur secondary to anterior [[uveitis]] (inflammation of the inside of the eye).{{cn|date=November 2025}}

===Anterior lens luxation===
With anterior lens luxation, the lens pushes into the [[iris (anatomy)|iris]] or actually enters the [[anterior chamber]] of the eye. This can cause glaucoma, uveitis, or damage to the [[cornea]]. Uveitis (inflammation of the eye) causes the pupil to constrict ([[miosis]]) and trap the lens in the anterior chamber, leading to an obstruction of outflow of [[aqueous humour]] and subsequent increase in ocular pressure (glaucoma).&lt;ref&gt;{{cite web | last = Ketring | first = Kerry I. | title = Emergency Treatment for Anterior Lens Luxation | work = Proceedings of the North American Veterinary Conference | year = 2006 | url = http://www.ivis.org/proceedings/navc/2006/SAE/310.pdf?LA=1 | format = PDF | access-date = 2007-02-22 | archive-url = https://web.archive.org/web/20070929094429/http://www.ivis.org/proceedings/navc/2006/SAE/310.pdf?LA=1 | archive-date = 2007-09-29 | url-status = dead }}&lt;/ref&gt; Better prognosis is valued in lens replacement surgery (retained vision and normal intraocular pressure) when it is performed before the onset of [[secondary glaucoma]].&lt;ref name=Glover&gt;{{cite journal |vauthors=Glover T, Davidson M, Nasisse M, Olivero D |title=The intracapsular extraction of displaced lenses in dogs: a retrospective study of 57 cases (1984-1990) |journal=[[Journal of the American Animal Hospital Association]] |volume=31 |issue=1 |pages=77–81 |year=1995 |doi=10.5326/15473317-31-1-77 |pmid=7820769}}&lt;/ref&gt; Glaucoma secondary to anterior lens luxation is less common in cats than dogs due to their naturally deeper anterior chamber and the liquification of the [[vitreous humour]] secondary to chronic inflammation.&lt;ref&gt;{{cite web | last = Peiffer | first = Robert L. Jr. | title = Diseases of the Lens in Dogs and Cats | work = Proceedings of the 29th World Congress of the World Small Animal Veterinary Association | year = 2004 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2004&amp;PID=8713&amp;O=Generic | access-date = 2007-02-22 }}&lt;/ref&gt; Anterior lens luxation is considered to be an ophthalmological emergency.{{cn|date=November 2025}}

===Posterior lens luxation===
With posterior lens luxation, the lens falls back into the vitreous humour and lies on the floor of the eye. This type causes fewer problems than anterior lens luxation, although glaucoma or ocular inflammation may occur. Surgery is used to treat dogs with significant symptoms. Removal of the lens before it moves to the anterior chamber may prevent secondary glaucoma.&lt;ref name=Glover/&gt;

===Lens subluxation===
Lens subluxation is also seen in dogs and is characterized by a partial displacement of the lens. It can be recognized by trembling of the iris ([[iridodonesis]]) or lens ([[phacodonesis]]) and the presence of an aphakic crescent (an area of the pupil where the lens is absent).&lt;ref&gt;{{cite web | title = Lens | work = The Merck Veterinary Manual | year = 2006 | url = http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/30112.htm | access-date = 2007-02-22 | archive-date = 2003-04-05 | archive-url = https://web.archive.org/web/20030405153208/http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/30112.htm | url-status = dead }}&lt;/ref&gt; Other signs of lens subluxation include mild [[conjunctiva]]l redness, vitreous humour degeneration, prolapse of the vitreous into the anterior chamber, and an increase or decrease of anterior chamber depth.&lt;ref name=Canvet&gt;{{cite journal |vauthors=Grahn B, Storey E, Cullen C |title=Diagnostic ophthalmology. Congenital lens luxation and secondary glaucoma |journal=Canadian Veterinary Journal |volume=44 |issue=5 |pages=427, 429–30 |year=2003 |pmid=12757137 |pmc=340155}}&lt;/ref&gt; Removal of the lens before it completely luxates into the anterior chamber may prevent secondary glaucoma.&lt;ref name=Glover/&gt; Extreme degree of luxation of lens is called &quot;lenticele&quot; in which lens comes out of the eyeball and becomes trapped under the Tenon's capsule or conjunctiva.&lt;ref&gt;Shah SIA et al: Concise Ophthalmology Text &amp; Atals. 5th ed. Param B (Pvt.) Ltd. 2018: 60-61&lt;/ref&gt; A nonsurgical alternative treatment involves the use of a miotic to constrict the pupil and prevent the lens from luxating into the anterior chamber.&lt;ref&gt;{{cite journal |vauthors=Binder DR, Herring IP, Gerhard T |title=Outcomes of nonsurgical management and efficacy of demecarium bromide treatment for primary lens instability in dogs: 34 cases (1990-2004) |journal=Journal of the American Veterinary Medical Association |volume=231 |issue=1 |pages=89–93 |year=2007 |pmid=17605669 |doi=10.2460/javma.231.1.89}}&lt;/ref&gt;

===Breed predisposition===
Terrier breeds are predisposed to lens luxation, and it is probably inherited in the [[Sealyham Terrier]], [[Jack Russell Terrier]], [[Fox Terrier (Wire)|Wirehaired Fox Terrier]], [[Rat Terrier]], [[Teddy Roosevelt Terrier]], [[Tibetan Terrier]],&lt;ref name=Gelatt&gt;{{cite book|editor=Gelatt, Kirk N.|title=Veterinary Ophthalmology|edition=3rd|publisher=Lippincott, Williams &amp; Wilkins|year=1999|isbn=0-683-30076-8}}&lt;/ref&gt; [[Bull Terrier (Miniature)|Miniature Bull Terrier]], [[Shar Pei]], and [[Border Collie]].&lt;ref&gt;{{cite web | last = Petersen-Jones | first = Simon M. | title = Conditions of the Lens | work = Proceedings of the 28th World Congress of the World Small Animal Veterinary Association | year = 2003 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2003&amp;PID=6686&amp;O=Generic | access-date = 2007-02-22 }}&lt;/ref&gt; The mode of inheritance in the Tibetan Terrier&lt;ref name=Canvet/&gt; and Shar Pei&lt;ref&gt;{{cite journal |vauthors=Lazarus J, Pickett J, Champagne E |title=Primary lens luxation in the Chinese Shar Pei: clinical and hereditary characteristics |journal=Veterinary Ophthalmology |volume=1 |issue=2–3 |pages=101–107 |year=1998 |pmid=11397217 |doi=10.1046/j.1463-5224.1998.00021.x}}&lt;/ref&gt; is likely [[recessive gene|autosomal recessive]]. [[Labrador Retriever]]s and [[Australian Cattle Dog]]s are also predisposed.&lt;ref&gt;{{cite journal |vauthors=Johnsen D, Maggs D, Kass P |title=Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999-2004) |journal=Journal of the American Veterinary Medical Association |volume=229 |issue=8 |pages=1270–4 |year=2006 |pmid=17042730 |doi=10.2460/javma.229.8.1270|doi-access=free }}&lt;/ref&gt;

==Systemic associations in humans==
In humans,  a number of systemic conditions  are associated with ectopia lentis:&lt;ref name=&quot;Eifrig&quot;&gt;Eifrig CW, Eifrig DE. [http://www.emedicine.com/OPH/topic55.htm &quot;Ectopia Lentis&quot;]. eMedicine.com. November 24, 2004.&lt;/ref&gt;

More common:
* [[Marfan syndrome]] (upward and outward)&lt;ref name=&quot;RobinsonGodfrey2004&quot;&gt;{{cite book|author1=Peter Nicholas Robinson|author2=Maurice Godfrey|title=Marfan syndrome: a primer for clinicians and scientists|url=https://books.google.com/books?id=eX4B9WASDpAC&amp;pg=PA5|access-date=12 April 2010|year=2004|publisher=Springer|isbn=978-0-306-48238-0|pages=5–}}&lt;/ref&gt;
* [[Homocystinuria]] (downward and inwards)&lt;ref name=&quot;RobinsonGodfrey2004&quot;/&gt;
* [[Weill–Marchesani syndrome]]
* [[Sulfite oxidase deficiency]]
* [[Molybdenum cofactor deficiency]]
* [[Hyperlysinemia]]
Less common:
* [[Ehlers–Danlos syndrome]]
* [[Crouzon disease]]
* [[Refsum syndrome]]
* [[Kniest syndrome]]
* [[Mandibulofacial dysostosis]]
* [[Sturge–Weber syndrome]]
* [[Conradi syndrome]]
* [[Pfaundler syndrome]]
* [[Pierre Robin syndrome]]
* [[Wildervanck syndrome]]
* [[Sprengel deformity]]

==See also==
* [[List of systemic diseases with ocular manifestations]]

==References==
{{Reflist}}

== External links ==
{{Medical resources
|  DiseasesDB  = 29374
|  ICD10   = {{ICD10|H|27|1|h|25}}, {{ICD10|Q|12|1|q|10}}
|  ICD9   = {{ICD9|743.37}}
|  ICDO   = 
|  OMIM   = 225100
|  MedlinePlus = 
|  eMedicineSubj = oph
|  eMedicineTopic = 55
|  MeshID   = D004479
}}
* [https://www.ncbi.nlm.nih.gov/books/NBK84111/ GeneReviews/NCBI/NIH/UW entry on ADAMTSL4-Related Eye Disorders, Autosomal Recessive Isolated Ectopia Lentis, Ectopia Lentis et Pupillae]

{{Eye pathology}}
{{Congenital malformations and deformations of eye, ear, face and neck}}

[[Category:Dog diseases]]
[[Category:Cat diseases]]
[[Category:Congenital disorders of eyes]]
[[Category:Disorders of lens]]