Ectopia lentis 3940682 215523194 2008-05-28T16:02:58Z DOI bot 6652755 Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. {{Infobox_Disease | Name = {{PAGENAME}} | Image = | Caption = | 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 }} [[Image:Luxating lens - anterior.JPG|thumb|Anterior lens luxation in a dog]] [[Image:Feline lens luxation 2.JPG|thumb|Anterior lens luxation with cataract formation in a cat]] '''Ectopia lentis''' is a displacement or malposition of the [[eye]]'s [[lens (anatomy)|crystalline 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). Lens luxation in cats can occur secondary to anterior [[uveitis]] (inflammation of the inside of the eye). ===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).<ref>{{cite web | last = Ketring | first = Kerry I. | title = Emergency Treatment for Anterior Lens Luxation | work = Proceedings of the North American Veterinary Conference | date = 2006 | url = http://www.ivis.org/proceedings/navc/2006/SAE/310.pdf?LA=1 | format = PDF | accessdate = 2007-02-22 }}</ref> Surgery to remove the lens has a higher success rate (retained vision and normal intraocular pressure) when it is performed before the onset of secondary glaucoma.<ref name=Glover>{{cite journal |author=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=J Am Anim Hosp Assoc |volume=31 |issue=1 |pages=77–81 |year=1995 |pmid=7820769}}</ref> 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.<ref>{{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 | date = 2004 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2004&PID=8713&O=Generic | accessdate = 2007-02-22 }}</ref> Anterior lens luxation is considered to be an ophthalmological emergency. ===Posterior lens luxation=== With posterior lens luxation, the lens falls back into the vitreous humour and lays on the floor of the eye. This type causes less 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.<ref name=Glover/> ===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).<ref>{{cite web | title = Lens | work = The Merck Veterinary Manual | date = 2006 | url = http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/30112.htm | accessdate = 2007-02-22 }}</ref> 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.<ref name=Canvet>{{cite journal |author=Grahn B, Storey E, Cullen C |title=Diagnostic ophthalmology. Congenital lens luxation and secondary glaucoma |journal=Can Vet J |volume=44 |issue=5 |pages=427, 429–30 |year=2003 |pmid=12757137}}</ref> Removal of the lens before it completely luxates into the anterior chamber may prevent secondary glaucoma.<ref name=Glover/> A nonsurgical alternative involves the use of a miotic to constrict the pupil and prevent the lens from luxating into the anterior chamber.<ref>{{cite journal |author=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=J. Am. Vet. Med. Assoc. |volume=231 |issue=1 |pages=89–93 |year=2007 |pmid=17605669 |doi=10.2460/javma.231.1.89}}</ref> ===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]], [[Tibetan Terrier]],<ref name=Gelatt>{{cite book|author=Gelatt, Kirk N. (ed.)|title=Veterinary Ophthalmology|edition=3rd ed.|publisher=Lippincott, Williams & Wilkins|year=1999|id=ISBN 0-683-30076-8}}</ref> [[Bull Terrier (Miniature)|Miniature Bull Terrier]], [[Shar Pei]], and [[Border Collie]].<ref>{{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 | date = 2003 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2003&PID=6686&O=Generic | accessdate = 2007-02-22 }}</ref> The mode of inheritance in the Tibetan Terrier<ref name=Canvet/> and Shar Pei<ref>{{cite journal |author=Lazarus J, Pickett J, Champagne E |title=Primary lens luxation in the Chinese Shar Pei: clinical and hereditary characteristics |journal=Vet Ophthalmol |volume=1 |issue=2-3 |pages=101–107 |year=1998 |pmid=11397217 |doi=10.1046/j.1463-5224.1998.00021.x}}</ref> is likely [[recessive gene|autosomal recessive]]. [[Labrador Retriever]]s and [[Australian Cattle Dog]]s are also predisposed.<ref>{{cite journal |author=Johnsen D, Maggs D, Kass P |title=Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999-2004) |journal=J Am Vet Med Assoc |volume=229 |issue=8 |pages=1270–4 |year=2006 |pmid=17042730 |doi=10.2460/javma.229.8.1270}}</ref> ==Systemic associations in humans== In humans, there are a number of systemic conditions that are associated with ectopia lentis<ref name="Eifrig">Eifrig CW, Eifrig DE. [http://www.emedicine.com/OPH/topic55.htm "Ectopia Lentis"]. eMedicine.com. November 24, 2004.</ref>: More common: *[[Marfan syndrome]] *[[Homocystinuria]] *[[Weill-Marchesani syndrome]] *[[Sulfite oxidase 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]] ==References== {{reflist|2}} ==See also== *[[List of eye diseases and disorders]] *[[List of systemic diseases with ocular manifestations]] {{Eye pathology}} {{Congenital malformations and deformations of eye, ear, face and neck}} [[Category:Dog diseases]] [[Category:Cat diseases]] [[Category:Ophthalmology]]