What are Uveitis and its Causes?

What is Uveitis?

Uveitis is the inflammation of the middle layer of the eye, located between the sclera on the outside and the retina on the inside, which affects the iris, ciliary body, pars plana, and/or choroid. Sometimes, by extension, it can also affect the retina.

What are the Types of Uveitis?

Uveitis can be classified according to its etiology into five large groups: idiopathic, diseases of autoimmune etiology, infections, primarily ocular syndromes, and masking syndromes that encompass a multitude of processes, among which tumors stand out. In the latter case, uveitis would be an ocular extension of a primary tumor.

In this sense, uveitis is considered idiopathic in almost half of the cases, which means that it does not occur in the context of any other disease and that its cause is unknown. 

However, in the other half of cases, its cause can be diagnosed and in about a third of patients, uveitis is caused by rheumatic disease, among which are: juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis, arthritis associated with enteropathies, reactive arthritis, Behçet’s disease, some systemic vasculitides, and sarcoidosis, among others.

Likewise, depending on the anatomical location affected, uveitis is classified as anterior, intermediate, posterior uveitis, or panuveitis (if they affect all structures). In general, the main symptoms are excessive blinking, blurred vision, high sensitivity to light or redness, and pain in the eyes. 

Specifically, anterior uveitis usually presents with pain, ocular redness, and photophobia of more or less sudden onset; There is rarely a decrease in visual acuity and, if it does occur, it is usually mild. 

However, in posterior uveitis there is decreased visual acuity, the vision of “flying flies” and occasionally photophobia; on the contrary, there is usually no pain or eye redness.


Regarding the incidence of uveitis, although it can be suffered at any age, it is more typical of young people between 22 and 44 years of age.

Symptoms of Uveitis?


Uveitis presents with different symptoms depending on its location. The anterior and intermediate ones present eye redness and pain, tearing, photophobia (intolerance to light), and blurred vision. 

On the other hand, posterior uveitis usually presents with floaters (perception of floaters) and variable vision loss depending on the size and location of the lesions.

The inflammation can appear only in one eye or appear in both (simultaneously or separated in time). It can present acutely and suddenly or have a chronic course with a more gradual onset and a longer duration of symptoms. Recurrences or relapses may be frequent.


Treatment of uveitis will depend on the underlying cause of the inflammation and should be started as soon as possible. In some uveitis of infectious origin, treatment with antibiotics can be curative.

In most patients, corticosteroids are the mainstay of treatment in the acute phase and can be used in the form of eye drops, injections around or inside the eye, or systemically (orally, intramuscularly, or intravenously).

In some uveitis of immunological origin, chronic, difficult to manage, or with complications derived from the use of corticosteroids, the use of immunomodulatory drugs may be necessary to control inflammation (for a long time or even throughout life). Some of these drugs may have side effects that require close monitoring.

In some cases, it may be necessary to perform a surgical intervention for diagnostic purposes or to treat some of the complications associated with intraocular inflammation (especially in chronic forms), such as cataracts, glaucoma, persistent vitreous opacity, intraocular hemorrhages, or retinal detachment.

Causes of Uveitis?

The origin of intraocular inflammation can be very diverse. Uveitis may reflect a disease that is occurring in other parts of the body and that may have gone unnoticed, becoming an alarm signal.

We divide the causes of uveitis into infectious and non-infectious. Among the infectious agents that can cause intraocular inflammation, viruses (such as herpes), bacteria (such as tuberculosis or syphilis), or parasites (such as toxoplasmosis) stand out.

Toxoplasmosis is the most common infectious cause. This parasite, which is ingested through contaminated meat or vegetables, encysts in the retina causing chorioretinitis which, once cured, results in the appearance of a scar. When this occurs in the macula (central part of the retina), the loss of vision that it causes is severe.

Non -infectious uveitis can only affect the eye or be related to general diseases such as juvenile idiopathic arthritis, ankylosing spondylitis, Behçet’s disease, inflammatory bowel disease, or sarcoidosis, among many others.

It should be taken into account that in about 35% of patients the exact cause or origin of the inflammation is never found and they are considered idiopathic uveitis.