The uveal tract may become inflamed because of infection, injury, a bodywide autoimmune disorder (which causes the body to attack its own tissues), or for unknown reasons.
Symptoms may include eye ache, eye redness, floaters, loss of vision, or a combination.
Treatment typically includes corticosteroids (as eye drops, taken by mouth, or injected into or around the eye), drops that dilate and relax the pupil in the affected eye, and sometimes drugs that suppress the immune system.
The uveal tract consists of three structures:
The ciliary body
The iris, the colored ring around the black pupil, opens and closes to let more or less light into the eye, just like the shutter in a camera.
The ciliary body is the set of muscles that, by contracting, allows the lens to become thicker so the eye can focus on nearby objects. By relaxing, the ciliary body allows the lens to become thinner so the eye can focus on distant objects. This process is called accommodation.
The choroid, which lines part of the back part of the eyeball, extends from the edge of the ciliary muscles to the optic nerve at the back of the eye. The choroid lies between the retina on the inside and the sclera on the outside. The choroid contains both pigmented cells and blood vessels that nourish the inside parts of the eye, particularly the retina.
A View of the Uveal Tract
The uveal tract consists of three structures: the iris, ciliary body, and choroid.
Part or all of the uveal tract may become inflamed. Inflammation limited to part of the uveal tract is named according to its location:
Anterior uveitis is inflammation in the front of the uveal tract, including the iris.
Intermediate uveitis is inflammation in the middle of the uveal tract, and typically also involves the jellylike substance that fills the eyeball (called the vitreous humor).
Posterior uveitis is inflammation in the back of the uveal tract and can involve the retina and choroid.
Panuveitis is inflammation that affects the entire uveal tract.
Sometimes uveitis is referred to by the name of the specific part that is inflamed. For example, iritis is inflammation of the iris, choroiditis is inflammation of the choroid, and chorioretinitis is inflammation that involves both the choroid and the overlying retina. Inflammation of the uveal tract is limited to one eye in many people with uveitis but may involve both eyes.
Causes of Uveitis
The inflammation has many possible causes. Some causes are limited to the eye itself, and others are disorders that affect the entire body. In most people, no cause is identified, and they are said to have idiopathic uveitis (or uveitis of unknown cause).
Many people with uveitis have a disorder that also affects organs elsewhere in the body. These include inflammatory diseases, such as Behçet syndrome Behçet Disease Behçet disease is chronic blood vessel inflammation (vasculitis) that can cause painful mouth and genital sores, skin lesions, and eye problems. The joints, nervous system, and digestive tract... read more , ankylosing spondylitis Ankylosing Spondylitis Ankylosing spondylitis is a spondyloarthritis characterized by inflammation of the spine (spondylitis), large joints, and fingers and toes, resulting in stiffness and pain. Prolonged joint pain... read more , juvenile idiopathic arthritis Juvenile Idiopathic Arthritis (JIA) Juvenile idiopathic arthritis is a group of related childhood diseases that begin by age 16 and involve persistent or recurring inflammation of the joints. Certain forms of juvenile idiopathic... read more , sarcoidosis Sarcoidosis Sarcoidosis is a disease in which abnormal collections of inflammatory cells (granulomas) form in many organs of the body. Sarcoidosis usually develops in people aged 20 to 40 years, most often... read more , reactive arthritis Reactive Arthritis Reactive arthritis (previously called Reiter syndrome) is a spondyloarthritis causing inflammation of the joints and tendon attachments at the joints, often related to an infection. Joint pain... read more , inflammatory bowel diseases Overview of Inflammatory Bowel Disease (IBD) In inflammatory bowel diseases, the intestine (bowel) becomes inflamed, often causing recurring abdominal pain and diarrhea. The 2 primary types of inflammatory bowel disease (IBD) are Crohn... read more (Crohn disease Crohn Disease Crohn disease is an inflammatory bowel disease where chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both and may affect any part of the... read more and ulcerative colitis Ulcerative Colitis Ulcerative colitis is a chronic inflammatory bowel disease in which the large intestine (colon) becomes inflamed and ulcerated (pitted or eroded), leading to flare-ups (bouts or attacks) of... read more ), tubulointerstitial nephritis and uveitis (TINU), and, among those of Asian, Asian Indian, American Indian, and Hispanic ancestry, Vogt-Koyanagi-Harada disease. Some people have widespread infections, such as tuberculosis Tuberculosis (TB) Tuberculosis is a chronic contagious infection caused by the airborne bacteria Mycobacterium tuberculosis. It usually affects the lungs, but almost any organ can be involved. Tuberculosis... read more , syphilis Syphilis Syphilis is a sexually transmitted infection caused by the bacteria Treponema pallidum. It can occur in three stages of symptoms, separated by periods of apparent good health. Syphilis... read more , or Lyme disease Lyme Disease Lyme disease is a tick-transmitted infection caused by Borrelia species, primarily by Borrelia burgdorferi and sometimes by Borrelia mayonii in the United States. These... read more .
Other possible causes include infections that may affect only the eye, such as herpes Herpes Simplex Virus (HSV) Infections Herpes simplex virus infection causes recurring episodes of small, painful, fluid-filled blisters on the skin, mouth, lips (cold sores), eyes, or genitals. This very contagious viral infection... read more (caused by herpes simplex virus) infection, shingles Shingles Shingles is a painful skin rash caused by a viral infection that results from reactivation of the varicella-zoster virus, the virus that causes chickenpox. What causes the virus to reactivate... read more (caused by varicella-zoster virus), toxoplasmosis Toxoplasmosis Toxoplasmosis is infection caused by the protozoan parasite Toxoplasma gondii. Infection occurs when people unknowingly ingest toxoplasma cysts from cat feces or eat contaminated meat... read more , and cytomegalovirus Cytomegalovirus (CMV) Infection Cytomegalovirus infection is a common herpesvirus infection with a wide range of symptoms: from no symptoms to fever and fatigue (resembling infectious mononucleosis) to severe symptoms involving... read more . Cytomegalovirus occurs mainly in people with compromised immune systems, such as those infected with human immunodeficiency virus (HIV) or who take drugs that suppress the immune system.
Eye injuries Overview of Eye Injuries The structure of the face and eyes is well suited for protecting the eyes from injury. The eyeball is set into the orbit, a socket surrounded by a strong, bony ridge. The eyelids close quickly... read more are a common cause of anterior uveitis.
Although rare, some drugs (such as pamidronate, rifabutin, sulfonamide antibiotics, cidofovir, and checkpoint inhibitors like ipilimumab) can cause uveitis.
Symptoms of Uveitis
The early symptoms of uveitis may be mild or severe, depending on which part of the uveal tract is affected and the amount of inflammation.
Anterior uveitis typically has the most troublesome symptoms. Severe ache in the eye, redness of the conjunctiva, pain with exposure to bright light, and a slight decrease in vision are typical. A doctor may be able to see prominent blood vessels on the surface of the eye near the edge of the cornea, white blood cells floating in the fluid that fills the front part of the eye (aqueous humor), and deposits of white blood cells on the inside surface of the cornea.
Intermediate uveitis is typically painless. Vision may be decreased, and the person may see increasing numbers of irregular floating black spots (floaters Eye Flashes and Floaters Eye flashes are a person's perception of bright flashes of light, flickering lights, or streaks of light that do not correspond to external sources. Eye floaters are specks or strings that appear... read more ).
Posterior uveitis typically also causes decreased vision and floaters. The optic nerve may become inflamed (see Optic Neuritis Optic Neuritis Optic neuritis is inflammation of the optic nerve. Multiple sclerosis is the most common cause. Loss of vision may develop, and there may be pain with eye movement. Magnetic resonance imaging... read more ). Symptoms of this inflammation include loss of vision, which may vary from a small blind spot to total blindness.
Panuveitis may cause any combination of these symptoms.
Uveitis can rapidly damage the eye. It can cause long-term, vision-threatening complications, such as swelling of the macula, damage to the retina Overview of Retinal Disorders The retina is the transparent, light-sensitive structure at the back of the eye. The cornea and lens focus light onto the retina. The central area of the retina, called the macula, contains... read more , glaucoma Glaucoma Glaucomas are a group of eye disorders characterized by progressive optic nerve damage (often, but not always, associated with increased eye pressure) that can lead to irreversible loss of vision... read more , and cataracts Cataract A cataract is a clouding (opacity) of the lens of the eye that causes a progressive, painless loss of vision. Vision may be blurred, contrast may be lost, and halos may be visible around lights... read more . Many people have only one episode of uveitis. Others have periodic recurrences over months to years or chronic inflammation requiring long-term therapy.
Diagnosis of Uveitis
A doctor's evaluation
A doctor bases the diagnosis on the symptoms and a physical examination. During the examination, the doctor uses a slit lamp. A slit lamp Slit-Lamp Examination A person who has eye symptoms should be checked by a doctor. However, some eye disorders cause few or no symptoms in their early stages, so the eyes should be checked regularly (every 1 to 2... read more is an instrument that enables the doctor to examine the eye under high magnification. If the doctor suspects a disorder that also affects other organs, appropriate tests are done.
Treatment of Uveitis
Drugs to dilate the pupils
Sometimes other drugs or treatments
Uveitis treatment must start early to prevent permanent damage. Treatment almost always includes corticosteroids, usually given as eye drops. Corticosteroids can also be taken by mouth or injected into or around the eye. Drugs to dilate the pupils, such as homatropine or cyclopentolate drops, are also used.
Other drugs may be used to treat specific causes of uveitis. For example, if infection is the cause, drugs may be given to eliminate the infecting organism.
Occasionally, other treatments are necessary, such as surgery, use of a laser, or drugs taken by mouth or injected by vein (intravenously) or into the skin that suppress the immune system (immunosuppressants).