Uveitis occurs when the eye becomes inflamed (red and swollen).

Inflammation is the body's response to illness or infection.

Most cases of uveitis are linked to a problem with the immune system (the body's defence against infection and illness).

Rarely, uveitis may occur without the eye becoming red or swollen.

Immune system problems

Uveitis often occurs in people who have an underlying autoimmune condition (where the immune system mistakenly attacks healthy tissue).

Autoimmune conditions known to cause uveitis include:

Infection

Uveitis can also be caused by an infection, such as:

  • toxoplasmosis – an infection caused by a parasite
  • herpes simplex virus – the virus responsible for cold sores
  • varicella-zoster virus – the virus that causes chickenpox and shingles
  • cytomegalovirus – a common infection that doesn't usually cause any noticeable symptoms, but can cause sight-threatening uveitis in people with a lowered immune system
  • tuberculosis 
  • HIV and syphilis are rare causes

Other causes

Uveitis can also be caused by:

  • trauma or injury to the eyes, or eye surgery
  • some types of cancers, such as lymphoma, although this is a very rare cause of uveitis

Sometimes, a specific cause of uveitis can't be identified.

Gene HLA-B27

Although uveitis isn't passed down through families, a gene known as HLA-B27 has been linked to an increased risk of developing anterior uveitis (uveitis at the front of the eye).

About half of all people with anterior uveitis have the HLA-B27 gene. The gene has been found in people with certain autoimmune conditions, including ankylosing spondylitis, ulcerative colitis, psoriatic arthritis, Crohn's disease and reactive arthritis.

Page last reviewed: 07/02/2017

Next review due: 07/02/2020