Uveitis

What is Uveitis?

Uveitis is a group of inflammatory diseases of the eye that produces swelling and destroys eye tissues. These diseases can slightly reduce vision or lead to severe vision loss.

The term "uveitis" is used because the diseases often affect a part of the eye called the uvea. Nevertheless, uveitis is not limited to the uvea. These diseases can also affect the lens, retina, optic nerve, and vitreous, producing reduced vision or blindness. 

Uveitis may be caused by problems or diseases occurring in the eye or it can be part of an inflammatory disease affecting other parts of the body. 

It can happen at all ages and primarily affects people between 20 – 60 years old.

Uveitis can last for a short (acute) or a long (chronic) time. The severest forms of uveitis reoccur many times. 

Eye care professionals may describe the disease more specifically as:

• Anterior uveitis

• Intermediate uveitis

• Posterior uveitis

• Panuveitis uveitis 

Eye care professionals may also describe the disease as infectious or noninfectious uveitis.

What is the Uvea and What Parts of the Eye are Most Affected by Uveitis?

The uvea is the middle layer of the eye, which contains much of the eye's blood vessels. Located between the sclera, the eye's white outer coat, and the inner layer of the eye, called the retina, the uvea consists of the iris, ciliary body, and choroid:

Iris - The colored circle at the front of the eye. It defines eye color, secretes nutrients to keep the lens healthy, and controls the amount of light that enters the eye by adjusting the size of the pupil. 

Ciliary Body - It is located between the iris and the choroid. It helps the eye focus by controlling the shape of the lens and it provides nutrients to keep the lens healthy.

Choroid - A thin, spongy network of blood vessels, which primarily provides nutrients to the retina.

Uveitis disrupts vision by primarily causing problems with the lens, retina, optic nerve, and vitreous

What Causes Uveitis? 

Uveitis is caused by inflammatory responses inside the eye. Inflammation is the body's natural response to tissue damage, germs, or toxins. It produces swelling, redness, heat, and destroys tissues as certain white blood cells rush to the affected part of the body to contain or eliminate the insult.

Uveitis may be caused by:

• An attack from the body's own immune system (autoimmunity).

• Infections or tumors occurring within the eye or in other parts of the body.

• Injury to the eye.

• Toxins that may penetrate the eye.

The disease will cause symptoms, such as decreased vision, pain, light sensitivity, and increased floaters. 

In many cases the cause of uveitis is unknown.

Uveitis is usually classified by where it occurs in the eye.

What is Anterior Uveitis?

Anterior uveitis occurs in the front of the eye. It is the most common form of uveitis, predominantly occurring in young and middle-aged people. Many cases occur in healthy people and may only affect one eye but some are associated with rheumatologic, skin, gastrointestinal, lung and infectious diseases.

What is Intermediate Uveitis?

Intermediate uveitis is commonly seen in young adults. The center of the inflammation often appears in the vitreous. It has been linked to several disorders including, sarcoidosis and multiple sclerosis.

What is Posterior Uveitis?

Posterior uveitis is the least common form of uveitis. It primarily occurs in the back of the eye, often involving both the retina and the choroid. It is often called choroditis or chorioretinitis. There are many infectious and non-infectious causes to posterior uveitis.

What is Pan-Uveitis?

Pan-uveitis is a term used when all three major parts of the eye are affected by inflammation. Intermediate, posterior, and pan-uveitis are the most severe and highly recurrent forms of uveitis. They often cause blindness if left untreated.

Diseases Associated with Uveitis

Uveitis can be associated with many diseases including:

• AIDS

• Ankylosing spondylitis

• Behcet's syndrome

• CMV retinitis

• Herpes zoster infection

• Histoplasmosis

• Juvenile Idiopathic Arthritis

• Kawasaki disease

• Multiple sclerosis

• Psoriasis

• Reactive arthritis

• Rheumatoid arthritis

• Sarcoidosis

• Syphilis

Toxoplasmosis

• Tuberculosis

• Ulcerative colitis

• Vogt Koyanagi Harada's disease

What are the Symptoms of Uveitis?

Uveitis can affect one or both eyes. Symptoms may develop rapidly and can include:

• Blurred vision

• Dark, floating spots in the vision (floaters)

• Eye pain

• Redness of the eye

• Sensitivity to light (photophobia)

Anyone suffering eye pain, severe light sensitivity, and any change in vision should immediately be examined by an ophthalmologist. 

The signs and symptoms of uveitis depend on the type of inflammation. 

Acute anterior uveitis may occur in one or both eyes and in adults is characterized by eye pain, blurred vision, sensitivity to light, a small pupil, and redness.

Intermediate uveitis causes blurred vision and floaters. Usually it is not associated with pain.

Posterior uveitis can produce vision loss. This type of uveitis can only be detected during an eye examination.

Some forms of uveitis such as uveitis in children with Juvenile Idiopathic arthritis may be initially asymptomatic until a lot of damage is done to the eye.

How is uveitis detected?

Diagnosis of uveitis includes a thorough examination and the recording of the patient's complete medical history. Laboratory tests may be done to rule out an infection or an autoimmune disorder.

The eye exams used, include:

An Eye Chart or Visual Acuity Test - This test measures whether a patient's vision has decreased.

A Funduscopic Exam - The pupil is widened (dilated) with eye drops and then a light is shown through with an instrument called an ophthalmoscope to noninvasively inspect the back, inside part of the eye.

Ocular Pressure: - An instrument, such as a tonometer or a tonopen, measures the pressure inside the eye. Drops and nontoxic die that numb the eye may be used for this test.

A Slit Lamp Exam - A slit lamp noninvasively inspects much of the eye. It can inspect the front and back parts of the eye and allow measuring eye pressure.

Fundus photography and fluorescein angiography, which makes blood vessels easier to see, may help diagnosis and guide treatment.

How is Uveitis Treated?

Uveitis treatments primarily try to eliminate inflammation, alleviate pain, prevent further tissue damage, and restore any loss of vision. Depending on uveitis type and severity treatment may range from several weeks to many years. It may include streroid or non-steroidal anti-inflammatory eye drops or pills.  In difficult to control cases injection may be used or systemic immunomodulatory therapy could be initiated usually in conjunction with rheumatologist or uveitis specialist.

Uveitis may result in glaucoma, cataracts and retina damage.