Uveitis occurs when the middle layer of the eyeball gets inflamed (red and swollen). This layer, called the uvea, has many blood vessels that nourish the eye. Uveitis can damage vital eye tissue, leading to permanent vision loss.
There are 3 types of uveitis. They are based on which part of the uvea is affected.
Swelling of the uvea near the front of the eye is called anterior uveitis. It starts suddenly and symptoms can last up to 8 weeks. Some forms of anterior uveitis are ongoing, while others go away but keep coming back.
Swelling of the uvea in the middle of the eye is called intermediate uveitis. Symptoms can last for a few weeks to many years. This form can go through cycles of getting better, then getting worse.
Swelling of the uvea toward the back of the eye is called posterior uveitis. Symptoms can develop gradually and last for many years.
In severe cases, all layers may be involved.