Fuchs heterochromic iridocyclitis (FHI) (also known as Fuchs heterochromic cyclitis or Fuchs heterochromic uveitis) is a chronic

Chronic

Chronic may refer to:* Chronic , a disease that is long-lasting and reoccurring.* Chronic toxicity, a substance with toxic effects after continuous or repeated exposure* The Chronic, a 1992 album by Dr. Dre...

 unilateral (or rarely bilateral) iridocyclitis

Iridocyclitis

Iridocyclitis, a type of anterior uveitis, is a condition in which the uvea of the eye is inflamed.Iridocyclitis isInflammation of the iris and the ciliary body.- Symptoms :Symptoms include:* Photophobia* Redness* Watering of the eyes* Lacrimation...

 appearing with the triad of heterochromia

Heterochromia

In anatomy, heterochromia refers to a difference in coloration, usually of the iris but also of hair or skin. Heterochromia is a result of the relative excess or lack of melanin...

, predisposition to cataracts and 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...

, and keratitic precipitates on the posterior corneal surface. FHI can progress to chronic uveitis

Uveitis

Uveitis specifically refers to inflammation of the middle layer of the eye, termed the "uvea" but in common usage may refer to any inflammatory process involving the interior of the eye....

, cellular infiltration of the vitreous fluid, or chronic inflammation with possibility of retinal vasculitis

Retinal vasculitis

Retinal vasculitis is inflammation of the vascular branches of the retinal artery, caused either by primary ocular disease processes, or as a specific presentation of any systemic form of vasculitis such as Behçet's disease, sarcoidosis, multiple sclerosis, or any form of systemic nectrozing...

 (rare). Absence of macular edema (important distinguishing factor from other forms of vitritis/uveitis), iris discolouration and pigmentation (either in form of Koeppe's nodules

Koeppe's nodules

Koeppe's nodules are small nodules seen at the inner margin of the iris in patients with granulomatous anterior uveitis, which occurs in conditions sich as sarcoidosis and tuberculosis...

 or Busacca nodules

Busacca nodules

Busacca nodules are inflammatory nodules located on the surface of the iris seen in granulomatous anterior uveitis such as Fuchs heterochromic iridocyclitis ....

) are other characteristics of FHI. Patients are often asymptomatic and the disease is often discovered through investigation of the cause of the heterochromia, though ironically, a rare number of FHI patients do not have the classic heterochromia. Neovascularisation, is possible and an anterior chamber

Anterior chamber

The anterior chamber is the fluid-filled space inside the eye between the iris and the cornea's innermost surface, the endothelium. Aqueous humor is the fluid that fills the anterior chamber. Hyphema and glaucoma are two main pathologies in this area. In hyphema, blood fills the anterior chamber...

 paracentesis

Paracentesis

Paracentesis is a medical procedure involving needle drainage of fluid from a body cavity, most commonly the peritoneal cavity in the abdomen.A related procedure is thoracocentesis, which is needle drainage of the chest cavity...

 of the eye, or cataract surgery can cause bleeding form the fragile vessels in the atrophic iris, causing blood in the collection, known as the Amsler sign

Amsler sign

Amsler sign also known as Amsler-Verrey sign is the name of the diagnostic finding seen in patients with Fuchs heterochromic iridocyclitis...

.

Causes

According to recent research not a single theory is able to explain the cause fully, however current plausible theories include infection with Toxoplasma gondii

Toxoplasma gondii

Toxoplasma gondii is a species of parasitic protozoa in the genus Toxoplasma. The definitive host of T. gondii is the cat, but the parasite can be carried by many warm-blooded animals . Toxoplasmosis, the disease of which T...

, Herpes simplex

Herpes simplex

Herpes simplex is a viral disease caused by both Herpes simplex virus type 1 and type 2 . Infection with the herpes virus is categorized into one of several distinct disorders based on the site of infection. Oral herpes, the visible symptoms of which are colloquially called cold sores or fever...

 virus, Rubella

Rubella

Rubella, commonly known as German measles, is a disease caused by the rubella virus. The name "rubella" is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is...

 (German Measles) induced uveitis, neurogenic causes, and autoimmune pathology.

Complications

• 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...
  
  
• Cataracts
• Decreased visual acuity (vision loss)
• Iris
  Iris (anatomy)
  The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
  
   atrophy
  Atrophy
  Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
  
  

History

First described using available patient presentations observed, by then world-renowned Austrian medical doctor and ophthalmologist, Ernst Fuchs

Ernst Fuchs (doctor)

Ernst Fuchs was an Austrian ophthalmologist and physician best known for his contribution to description and identification of Fuchs heterochromic iridocyclitis in 1906, Fuchs's dystrophy, and his contributions in the field of ophthalmology including but not limited to Fuchs spot...

(June 14, 1851-November 21, 1930) in 1906.