What is Uveitis?

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Uveitis means inflammation of the layer, called the uvea or uveal tract, surrounding the centre of the eyeball. However, ophthalmologists use the term uveitis to refer to a whole group of potentially very diverse pathologies but which all have one thing in common – the presence of an inflammatory process within the eye.

How many people does Uveitis affect?

The World Health Organization (WHO) classifies uveitis as a rare disease. Nevertheless, despite its low incidence, Uveitis still represents the third most common cause of preventable blindness in the developed world. Along with Diabetes Mellitus, Uveitis constitutes the main cause of blindness in the working age population and therefore has a high socio-economic impact.

According to the United States Centers for Disease Control and Prevention (CDC), approximately 10% of all cases of blindness in the US are caused by uveitis. In Spain, around 47,000 people suffer from uveitis.

Types of Uveitis

Uveitis is classified anatomically in function of the initial site of inflammation:

  • Anterior uveitis or “iritis”. Affects the front of the eye. It can be accompanied by redness, eye pain and sensitivity to light.
  • Intermediate uveitis. This type of uveitis applies to inflammation of the gelatinous substance (vitreous humour) that gives the eyeball its tone and fills the vitreous cavity. If the most peripheral portion of the retina (pars plana) is inflamed, known as “pars planitis”, then it may manifest signs such as the formation of “snowballs” (aggregates of inflammatory cells floating in the vitreous) and “snowbanks” (accumulations of inflammatory cells in the pars plana).
  • Posterior uveitis. Inflammation of the retina and/or choroid, located in the posterior portion of the eye.
  • Panuveitis. There is inflammation in the front and back of the eye.

Depending on the cause of the inflammation, uveitis is also classified as:

  • Infectious Uveitis. A multitude of pathogens can provoke uveitis. The most common intraocular infections are toxoplasmosis, tuberculosis, herpes, syphilis, etc.
  • Non-infectious, immune-mediated or "autoimmune" Uveitis. Autoimmune uveitis is due to an immune response disorder that produces an abnormal reaction from the immune system which attacks its own ocular structures. 

Substantiated information by:

Alfredo Adán Civera
Marina Mesquida Febrer
Víctor Llorens Bellés

Published: 20 February 2018
Updated: 3 December 2019


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