Retinal dysplasia is an eye disease affecting the retina

Retina

The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...

 of animals and, less commonly, humans. It is usually a nonprogressive disease and can be caused by viral

Virus

A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

 infections, drugs, vitamin A

Vitamin A

Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...

 deficiency, or genetic defects. Retinal dysplasia is characterized by folds or rosette

Rosette

-People:* Rosette , a French actress* Rosette Bir , a French sculptor* Clinton Rosette , a prominent citizen of DeKalb, Illinois...

s (round clumps) of the retinal tissue.

Retinal dysplasia in dogs

Most cases of retinal dysplasia in dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

s are hereditary

Heredity

Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...

. It can involve one or both retinas. Retinal dysplasia can be focal, multifocal, geographic, or accompanied by retinal detachment

Retinal detachment

Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blindness. It is a medical emergency.The retina is a...

. Focal and multifocal retinal dysplasia appears as streaks and dots in the central retina. Geographic retinal dysplasia appears as an irregular or horseshoe-shaped area of mixed hyper or hyporeflectivity in the central retina. Retinal detachment occurs with complete retinal dysplasia, and is accompanied by blindness in that eye. Cataract

Cataract

A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...

s or glaucoma

Glaucoma

Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...

 can also occur secondary to retinal dysplasia. Other causes of retinal dysplasia in dogs include infection with canine adenovirus

Infectious canine hepatitis

Infectious canine hepatitis is an acute liver infection in dogs caused by canine adenovirus type-1 . CAV-1 also causes disease in wolves, coyotes, and bears, and encephalitis in foxes. The virus is spread in the feces, urine, blood, saliva, and nasal discharge of infected dogs. It is contracted...

 or canine herpesvirus

Canine herpesvirus

Canine herpesvirus ' is a virus of the family Herpesviridae which most importantly causes a fatal hemorrhagic disease in puppies less than two to three weeks old. It is known to exist in the United States, Canada, Australia, Japan, England and Germany...

, or radiation

Radiation

In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

 of the eye in newborns.

Commonly affected breeds

• Bedlington Terrier
  Bedlington Terrier
  The Bedlington Terrier is a breed of terrier named after the mining town of Bedlington, Northumberland in North East England.- Description :Appearance:...
  
   - complete retinal dysplasia.
• Sealyham Terrier
  Sealyham Terrier
  The Sealyham Terrier is a dog breed of the terrier type. The Sealyham Terrier was originally developed in Wales.- History :thumb|right|A Sealyham Terrier photographed in 1915....
  
   - complete retinal dysplasia.
• Rottweiler
  Rottweiler
  The Rottweiler is a medium to large size breed of domestic dog that originated in Rottweil, Germany. The dogs were known as "Rottweil butchers' dogs" because they were used to herd livestock and pull carts laden with butchered meat and other products to market...
  
   - focal or multifocal.
• English Springer Spaniel
  English Springer Spaniel
  The English Springer Spaniel is a breed of gun dog traditionally used for flushing and retrieving game. It is an affectionate, excitable breed with an average lifespan of twelve to fourteen years. Descended from the Norfolk or Shropshire Spaniels of the mid-19th century, the breed has diverged into...
  
   - focal, multifocal, or geographic.
• American Cocker Spaniel
  American Cocker Spaniel
  The American Cocker Spaniel is a breed of sporting dog. It is a spaniel type dog that is closely related to the English Cocker Spaniel; the two breeds diverged during the 20th century due to differing breed standards in America and the UK...
  
   - focal or multifocal.
• Beagle
  Beagle
  The Beagle is a breed of small to medium-sized dog. A member of the Hound Group, it is similar in appearance to the Foxhound, but smaller, with shorter legs and longer, softer ears. Beagles are scent hounds, developed primarily for tracking hare, rabbit, and other game...
  
   - focal or multifocal.
• Cavalier King Charles Spaniel
  Cavalier King Charles Spaniel
  The Cavalier King Charles Spaniel is a small breed of Spaniel-type dog, and is classed as a toy dog by most kennel clubs. It is one of the most popular breeds in the United Kingdom. Since 2000, it has been growing in popularity in the United States. It is a smaller breed of spaniel, and Cavalier...
  
   - retinal folds, geographic, or retinal detachment.
• Labrador Retriever
  Labrador Retriever
  The Labrador Retriever is one of several kinds of retriever, a type of gun dog. A breed characteristic is webbed paws for swimming, useful for the breed's original purpose of retrieving fishing nets. The Labrador is the most popular breed of dog by registered ownership in Canada, the United...
  
   - focal, multifocal, geographic, or complete retinal dysplasia. It can also be seen in combination with a congenital skeletal disorder.
• Australian Shepherd
  Australian Shepherd
  The Australian shepherd is a breed of herding dog that was developed on ranches in the Western United States. Despite its name, the breed, commonly known as an Aussie, did not originate in Australia They acquired their name because some of the Australian sheepdogs arrived in the United States with...
  
   - retinal dysplasia occurs with other eye disorders, such as an oval pupil
  Pupil
  The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...
  
  , microcornea (small cornea), cataracts, and retinal detachment.

Retinal dysplasia in other animals

• Cat
  Cat
  The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
  
  s - Retinal dysplasia occurs in utero
  In utero
  In utero is a Latin term literally meaning "in the womb". In biology, the phrase describes the state of an embryo or fetus. In legal contexts, the phrase is used to refer to unborn children. Under common law, unborn children are still considered to exist for property transfer purposes.-See also:*...
  
   or in newborns infected with feline leukemia virus
  Feline leukemia virus
  Feline leukemia virus is a retrovirus that infects cats. FeLV can be transmitted between infected cats when the transfer of saliva or nasal secretions is involved. If not defeated by the animal’s immune system, the virus can be lethal...
  
   or feline panleukopenia
  Feline panleukopenia
  Feline panleukopenia virus , also known as Feline infectious enteritis, Feline distemper, feline ataxia, or cat plague, is a viral infection affecting cats, both domesticated and wild feline species. It is caused by feline parvovirus, a close relative of both type 2 canine parvovirus and mink...
  
  , which cause necrosis
  Necrosis
  Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
  
   and disorganization of the retina. It appears as folds and rosettes.
• Cattle
  Cattle
  Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
  
   - Retinal dysplasia occurs in utero through infection with bovine viral diarrhea
  Flaviviridae
  The Flaviviridae are a family of viruses that are primarily spread through arthropod vectors . The family gets its name from Yellow Fever virus, a type virus of Flaviviridae; flavus means yellow in Latin...
  
  . It is also inherited in Shorthorn
  Shorthorn
  The Shorthorn breed of cattle originated in the North East of England in the late 18th century. The breed was developed as dual purpose, suitable for both dairy and beef production; however there were always certain blood lines within the breed which emphasised one quality or the other...
  
  s and Hereford
  Hereford (cattle)
  Hereford cattle are a beef cattle breed, widely used both in intemperate areas and temperate areas, mainly for meat production.Originally from Herefordshire, England, United Kingdom, more than five million pedigree Hereford Cattle now exist in over 50 countries...
  
  s. Both forms often cause retinal detachment.
• Sheep - Retinal dysplasia occurs by in utero infection with bluetongue disease
  Bluetongue disease
  Bluetongue disease or catarrhal fever is a non-contagious, non-zoonotic, insect-borne, viral disease of ruminants, mainly sheep and less frequently cattle, goats, buffalo, deer, dromedaries and antelope...
  
  .
• Horse
  Horse
  The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
  
  s - Retinal dysplasia is bilateral, not inherited, and appears as multifocal or geographic disease. It is usually accompanied by other eye problems.
• Chicken
  Chicken
  The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
  
  s