Ectopia lentis is a displacement or malposition of the eye's 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
Ectopia Lentis in Marfan syndrome. Zonular fibers are being seen.
Although observed in humans and cats, ectopia lentis is most commonly seen in dogs. 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).
Anterior lens luxationedit
With anterior lens luxation, the lens pushes into the 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).[1] Better prognosis is valued in lens replacement surgery (retained vision and normal intraocular pressure) when it is performed before the onset of secondary glaucoma.[2] 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.[3] Anterior lens luxation is considered to be an ophthalmological emergency.
Posterior lens luxationedit
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.[2]
Lens subluxationedit
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).[4] Other signs of lens subluxation include mild conjunctival redness, vitreous humour degeneration, prolapse of the vitreous into the anterior chamber, and an increase or decrease of anterior chamber depth.[5] Removal of the lens before it completely luxates into the anterior chamber may prevent secondary glaucoma.[2] Extreme degree of luxation of lens is called "lenticele" in which lens comes out of the eyeball and becomes trapped under the Tenon's capsule or conjunctiva.[6] A nonsurgical alternative treatment involves the use of a miotic to constrict the pupil and prevent the lens from luxating into the anterior chamber.[7]
^Ketring, Kerry I. (2006). (PDF). Proceedings of the North American Veterinary Conference. Archived from the original (PDF) on 2007-09-29. Retrieved 2007-02-22.
^ abcGlover T, Davidson M, Nasisse M, Olivero D (1995). "The intracapsular extraction of displaced lenses in dogs: a retrospective study of 57 cases (1984-1990)". Journal of the American Animal Hospital Association. 31 (1): 77–81. doi:10.5326/15473317-31-1-77. PMID 7820769.
^Peiffer, Robert L. Jr. (2004). "Diseases of the Lens in Dogs and Cats". Proceedings of the 29th World Congress of the World Small Animal Veterinary Association. Retrieved 2007-02-22.
^"Lens". The Merck Veterinary Manual. 2006. Retrieved 2007-02-22.
^ abGrahn B, Storey E, Cullen C (2003). "Diagnostic ophthalmology. Congenital lens luxation and secondary glaucoma". Canadian Veterinary Journal. 44 (5): 427, 429–30. PMC340155. PMID 12757137.
^Shah SIA et al: Concise Ophthalmology Text & Atals. 5th ed. Param B (Pvt.) Ltd. 2018: 60-61
^Binder DR, Herring IP, Gerhard T (2007). "Outcomes of nonsurgical management and efficacy of demecarium bromide treatment for primary lens instability in dogs: 34 cases (1990-2004)". Journal of the American Veterinary Medical Association. 231 (1): 89–93. doi:10.2460/javma.231.1.89. PMID 17605669.
^Petersen-Jones, Simon M. (2003). "Conditions of the Lens". Proceedings of the 28th World Congress of the World Small Animal Veterinary Association. Retrieved 2007-02-22.
^Lazarus J, Pickett J, Champagne E (1998). "Primary lens luxation in the Chinese Shar Pei: clinical and hereditary characteristics". Veterinary Ophthalmology. 1 (2–3): 101–107. doi:10.1046/j.1463-5224.1998.00021.x. PMID 11397217.
^Johnsen D, Maggs D, Kass P (2006). "Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999-2004)". Journal of the American Veterinary Medical Association. 229 (8): 1270–4. doi:10.2460/javma.229.8.1270. PMID 17042730.
^Eifrig CW, Eifrig DE. "Ectopia Lentis". eMedicine.com. November 24, 2004.
^ abPeter Nicholas Robinson; Maurice Godfrey (2004). Marfan syndrome: a primer for clinicians and scientists. Springer. pp. 5–. ISBN978-0-306-48238-0. Retrieved 12 April 2010.
External linksedit
GeneReviews/NCBI/NIH/UW entry on ADAMTSL4-Related Eye Disorders, Autosomal Recessive Isolated Ectopia Lentis, Ectopia Lentis et Pupillae
March 15, 2024
ectopia, lentis, displacement, malposition, crystalline, lens, from, normal, location, partial, dislocation, lens, termed, lens, subluxation, subluxated, lens, complete, dislocation, lens, termed, lens, luxation, luxated, lens, ectopia, lentis, marfan, syndrom. Ectopia lentis is a displacement or malposition of the eye s 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 lentisEctopia Lentis in Marfan syndrome Zonular fibers are being seen SpecialtyMedical genetics Anterior lens luxation in a dogAnterior lens luxation with cataract formation in a cat Contents 1 Ectopia lentis in dogs and cats 1 1 Anterior lens luxation 1 2 Posterior lens luxation 1 3 Lens subluxation 1 4 Breed predisposition 2 Systemic associations in humans 3 See also 4 References 5 External linksEctopia lentis in dogs and cats editAlthough observed in humans and cats ectopia lentis is most commonly seen in dogs 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 Anterior lens luxation edit With anterior lens luxation the lens pushes into the 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 1 Better prognosis is valued in lens replacement surgery retained vision and normal intraocular pressure when it is performed before the onset of secondary glaucoma 2 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 3 Anterior lens luxation is considered to be an ophthalmological emergency Posterior lens luxation edit 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 2 Lens subluxation edit 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 4 Other signs of lens subluxation include mild conjunctival redness vitreous humour degeneration prolapse of the vitreous into the anterior chamber and an increase or decrease of anterior chamber depth 5 Removal of the lens before it completely luxates into the anterior chamber may prevent secondary glaucoma 2 Extreme degree of luxation of lens is called lenticele in which lens comes out of the eyeball and becomes trapped under the Tenon s capsule or conjunctiva 6 A nonsurgical alternative treatment involves the use of a miotic to constrict the pupil and prevent the lens from luxating into the anterior chamber 7 Breed predisposition edit Terrier breeds are predisposed to lens luxation and it is probably inherited in the Sealyham Terrier Jack Russell Terrier Wirehaired Fox Terrier Rat Terrier Teddy Roosevelt Terrier Tibetan Terrier 8 Miniature Bull Terrier Shar Pei and Border Collie 9 The mode of inheritance in the Tibetan Terrier 5 and Shar Pei 10 is likely autosomal recessive Labrador Retrievers and Australian Cattle Dogs are also predisposed 11 Systemic associations in humans editIn humans a number of systemic conditions are associated with ectopia lentis 12 More common Marfan syndrome upward and outward 13 Homocystinuria downward and inwards 13 Weill Marchesani syndrome Sulfite oxidase deficiency Molybdenum cofactor deficiency HyperlysinemiaLess 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 deformitySee also editList of systemic diseases with ocular manifestationsReferences edit Ketring Kerry I 2006 Emergency Treatment for Anterior Lens Luxation PDF Proceedings of the North American Veterinary Conference Archived from the original PDF on 2007 09 29 Retrieved 2007 02 22 a b c Glover T Davidson M Nasisse M Olivero D 1995 The intracapsular extraction of displaced lenses in dogs a retrospective study of 57 cases 1984 1990 Journal of the American Animal Hospital Association 31 1 77 81 doi 10 5326 15473317 31 1 77 PMID 7820769 Peiffer Robert L Jr 2004 Diseases of the Lens in Dogs and Cats Proceedings of the 29th World Congress of the World Small Animal Veterinary Association Retrieved 2007 02 22 Lens The Merck Veterinary Manual 2006 Retrieved 2007 02 22 a b Grahn B Storey E Cullen C 2003 Diagnostic ophthalmology Congenital lens luxation and secondary glaucoma Canadian Veterinary Journal 44 5 427 429 30 PMC 340155 PMID 12757137 Shah SIA et al Concise Ophthalmology Text amp Atals 5th ed Param B Pvt Ltd 2018 60 61 Binder DR Herring IP Gerhard T 2007 Outcomes of nonsurgical management and efficacy of demecarium bromide treatment for primary lens instability in dogs 34 cases 1990 2004 Journal of the American Veterinary Medical Association 231 1 89 93 doi 10 2460 javma 231 1 89 PMID 17605669 Gelatt Kirk N ed 1999 Veterinary Ophthalmology 3rd ed Lippincott Williams amp Wilkins ISBN 0 683 30076 8 Petersen Jones Simon M 2003 Conditions of the Lens Proceedings of the 28th World Congress of the World Small Animal Veterinary Association Retrieved 2007 02 22 Lazarus J Pickett J Champagne E 1998 Primary lens luxation in the Chinese Shar Pei clinical and hereditary characteristics Veterinary Ophthalmology 1 2 3 101 107 doi 10 1046 j 1463 5224 1998 00021 x PMID 11397217 Johnsen D Maggs D Kass P 2006 Evaluation of risk factors for development of secondary glaucoma in dogs 156 cases 1999 2004 Journal of the American Veterinary Medical Association 229 8 1270 4 doi 10 2460 javma 229 8 1270 PMID 17042730 Eifrig CW Eifrig DE Ectopia Lentis eMedicine com November 24 2004 a b Peter Nicholas Robinson Maurice Godfrey 2004 Marfan syndrome a primer for clinicians and scientists Springer pp 5 ISBN 978 0 306 48238 0 Retrieved 12 April 2010 External links editGeneReviews NCBI NIH UW entry on ADAMTSL4 Related Eye Disorders Autosomal Recessive Isolated Ectopia Lentis Ectopia Lentis et Pupillae Retrieved from https en wikipedia org w index php title Ectopia lentis amp oldid 1212344252, wikipedia, wiki, book, books, library,
