Corneal dystrophy 3973736 219206946 2008-06-14T02:23:24Z Joelmills 794015 remove nonspecific site '''Corneal dystrophy''' is a group of disorders, characterised by a noninflammatory, inherited, bilateral opacity of the transparent front part of the [[eye]] called the ''[[cornea]]''. It is commonly seen in [[humans]] as well as [[dog]]s. It is rare in cats. [[Image:Corneal dystrophy 2.JPG|thumb|Corneal dystrophy in a dog]] ==Signs and symptoms== Corneal dystrophy may not significantly affect vision in the early stages. However, it does not require proper evaluation and treatment for restoration of optimal vision. It can, however, rarely cause [[Corneal ulcers in animals|corneal ulcer]]ation, especially with epithelial dystrophy. It appears as grayish white lines, circles, or clouding of the [[cornea]]. Corneal dystrophy can also have a crystalline appearance. ==Pathophysiology== A corneal dystrophy can be caused by an accumulation of extraneous material in the cornea - it can be in the form of [[lipid]]s or [[cholesterol]] crystals. ==Classification== Corneal dystrophies are commonly subdivided depending on its specific location within the cornea. It can be basically divided into ''anterior'', ''stromal'', or ''posterior'' according to the layer of the cornea affected by the dystrophy. [http://www.eyeworld.org/article.php?sid=3199] [http://www.bchealthguide.org/kbase/nord/nord455.htm] ==Treatment== Suboptimal vision caused by corneal dystrophy usually requires surgical intervention in the form of [[corneal transplantation]]. [[Penetrating keratoplasty]] is commonly performed for extensive corneal dystrophy. Corneal dystrophy in dogs usually does not cause any problems and treatment is not required.<ref>{{cite web | last = Sapienza | first = John S. | title = Corneal Diseases of Dogs and Cats | work = Proceedings of the 27th World Congress of the World Small Animal Veterinary Association | date = 2002 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2002&PID=2647 | accessdate = 2007-03-04 }}</ref> ==Prognosis== Early stages may be asymptomatic and may not require any intervention. Initial treatment may include hypertonic eyedrops and/or ointment to reduce the corneal edema and may offer symptomatic improvement prior to surgical intervention. With penetrating keratoplasty (corneal transplant), the long term results are good-excellent. Recent surgical improvements have been made which have increased the success rate for this procedure. However, recurrence of the disease in the donor graft is not ruled out. ==Corneal dystrophy in dogs: Commonly affected breeds== Many breeds are affected by corneal dystrophy with many different appearances. These breeds most commonly have these criteria.<ref name=Gelatt_1999>{{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> *[[Afghan Hound]] *[[Airedale Terrier]] - occurs at 4 to 12 months of age in the central cornea. It is progressive and can cause decreased vision. *[[Alaskan Malamute]] - occurs at greater than two years of age in the central cornea. *[[Beagle]] - has a nebular, race track, or arcing appearance. *[[Bearded Collie]] - occurs at greater than one year of age in the lateral or central cornea and can affect just one eye. *[[Bichon Frise]] - occurs at greater than two years of age in the inferior or central cornea. *[[Cavalier King Charles Spaniel]] - occurs at two to four years of age in the central cornea. *[[American Cocker Spaniel]] *[[Rough Collie]] - occurs at one to four years of age in the inferior or central cornea. *[[English Toy Spaniel]] - occurs at two to five years of age and has a crystalline, circular appearance. *[[German Shepherd Dog]] - occurs at one to six years of age and is usually oval. *[[Golden Retriever]] - occurs at less than two years of age and can be progressive. *[[Italian Greyhound]] - occurs in young dogs and is focal. *[[Lhasa Apso]] - oval appearance. *[[Mastiff]] - oval appearance. *[[Miniature Pinscher]] - occurs at one to two years of age and is oval. *[[Norwich Terrier]] - peripheral cornea. *[[Pembroke Welsh Corgi]] - occurs in young dogs and can include blood vessels and pigmentation. *[[Pointer (dog)|Pointer]] - gray, hazy ring. *[[Poodle]] - occurs at greater than one year of age. *[[Samoyed]] - oocurs at six months to two years of age and is gray and round. *[[Shetland Sheepdog]] - occurs at two to four years of age as multiple gray/white rings. It can develop into a [[corneal ulcer]]. *[[Siberian Husky]] - occurs at five months to two years of age and is gray and oval. *[[Weimaraner]] - Occurs at one to eight years of age in the central cornea. *[[Whippet]] - occurs at three to five years of age in the central cornea. ==Corneal endothelial dystrophy== Corneal endothelial dystrophy is an age-related change that affects the inner layer of the corneal, the [[Corneal endothelium|endothelium]]. Leakage of fluid into the cornea causes [[edema]], causing a bluish appearance. This will eventually involve the whole cornea. [[Bullous keratopathy]] ([[blister]]s in the cornea) may also form, leading to nonhealing and recurrent corneal ulceration. [[Hyperosmotic]] agents are sometimes used topically for treatment, but success with these medications is inconsistent and can cause irritation. Bad cases may require a [[corneal transplant]] or [[thermokeratoplasty]], which is a grid of superficial burns to the cornea that causes anterior stromal fibers to contract and prevent fluid uptake by the stroma.<ref>{{cite journal |author=Michau T, Gilger B, Maggio F, Davidson M |title=Use of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs: 13 cases (1994-2001) |journal=J Am Vet Med Assoc |volume=222 |issue=5 |pages=607–12 |year=2003 |pmid=12619840 |doi=10.2460/javma.2003.222.607}}</ref> The most commonly affected breeds are the [[Boston Terrier]], [[Chihuahua (dog)|Chihuahua]], and [[Dachshund]].<ref name=Gelatt_1999/> The age of onset in the Boston is five to nine years and eight to thirteen years in the Chihuahua and Dachshund.<ref>{{cite web | last = Bjerk | first = Ellen | title = Ocular Disease of the Aging Dog | 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=8721&O=Generic | accessdate = 2007-03-04 }}</ref> The disease is similar to [[Fuch's dystrophy]] in humans. ==See also== *[[Recurrent corneal erosion]] *[[Keratoconus]] *[[Keratoglobus]] ==References== <div class="references-small"> <references/> </div> ==External links== *[http://www.nei.nih.gov/health/cornealdisease/index.asp Facts About the Cornea and Corneal Disease] The National Eye Institute (NEI) *[http://www.vmdb.org/dx2.html Discussion of corneal dystrophy in dogs] [[Category:Dog diseases]]