What is uveitis?
Uveitis is a wide range of inflammatory diseases of the eye, specifically the uvea. There are 3 basic layers of the eye – the sclera and cornea on the outside, the retina on the inside, and the uvea in between. The uvea is comprised mostly of blood vessels and connective tissue, including pigmented cells. The different parts of the uvea are the iris in the front, the ciliary body in the middle, and the choroid located behind these, which lies around most of the eye. Sometimes uveitis can affect parts of the eye other than uvea, such as retina, vitreous, or optic nerve.
Types of uveitis are based on what part of the eye is affected.
Uveitis has many causes. Most cases are due to autoimmune disease or infection, and there are some for which a cause is not found – so called “idiopathic” uveitis – which is treated as non-infectious inflammation. Other causes include trauma, medication-induced uveitis, and in rare instances, cancer.
These can vary by the type of uveitis, and can present in one or both eyes. Symptoms commonly include:
Any of the above symptoms can occur with any type of uveitis. There are even some types of uveitis that often present without any symptoms at all, such as uveitis associated with juvenile idiopathic arthritis.
“Cells” are actually white blood cells which are visible inside the eye on slit lamp examination when uveitis is active. The amount of cells the specialist can see help determine how severe inflammation is during a flare, and how aggressive treatment must be to combat it. Other measures of inflammation include “flare” in anterior uveitis and “haze” in intermediate and posterior uveitis, which are measures of protein and inflammatory debris within the eye that can appear in active uveitis.
The first step in diagnosing uveitis is a thorough history of illness and review of systems. The importance of this cannot be overstated, and is, unfortunately, sometimes overlooked.
Slit Lamp examination reveals the type of uveitis. Clinical testing can help to identify features or complications of uveitis such as vasculitis, macular edema, and glaucoma.
Blood work is almost always performed to look for well-known causes of the type of uveitis that presents. Outside referrals, imaging, and biopsies can be sought to evaluate for associated systemic disease.
Finally, response to therapy can sometimes help the physician to decide what type of uveitis is most likely present.
Autoimmune diseases associated with uveitis include:
Infectious causes can include:
Rarely, malignancies such as metastatic melanoma, leukemia, or lymphoma can also appear to be, or “masquerade” as, uveitis. Occasionally, diagnosis of uveitis can lead to discovery of potentially fatal disease and life-saving therapy.
The primary goal of treating uveitis is getting rid of inflammation as fast as possible.
Corticosteroids are the mainstay of therapy for acute uveitis of non-infectious causes, and can be used along with antibiotics in some cases of infectious uveitis. They can be given by drops, injection around or inside the eye, by mouth, or by intravenous infusion, depending on location and severity of inflammation. Unfortunately, they can never be depended upon for long term control of uveitis as they inevitably cause their own complications, such as cataract and glaucoma.
Other drops used in uveitis include cycloplegic drops (dilating drops), which are used to help limit light sensitivity, pain, and scarring of the iris to the lens (synechiae). Also, glaucoma from uveitis can be treated with drops that lower pressure in the eye.
Systemic therapy, by mouth, injection, or intravenous infusion, is sometimes necessary to treat stubborn cases of uveitis that recur after being treated acutely with steroids. Antibiotic or antiviral medication can be used, sometimes long term, to achieve remission.
A step-ladder approach to therapy has been adopted by most uveitis specialists to treat patients with stubborn or severe forms of non-infectious uveitis, with therapy again based on type and severity, as well as the extent of complications already suffered. This can include chemotherapy-style medications which require regular examinations and blood work monitoring. Side effects of medication can generally be avoided.
Surgery can be useful both for diagnosis and treatment of uveitis. Cataracts can be removed to improve vision as well as the specialist’s view inside the eye. Vitrectomy, removal of the gel center of the eye, can be used to perform biopsy as well as rid bothersome cells and debris to improve vision. Combined with steroid implants or laser therapy, it can also be used to treat active inflammation.
Vision loss is the number one complication of uveitis. Uveitis is the third leading cause of preventable blindness worldwide. This can be secondary to several other complications listed above. Some of these can be treated, but damage can become permanent.
Also, in treating uveitis, corticosteroids can lead to their own set of complications. This is why it is vital that inflammation be treated aggressively before these complications occur, and without long term dependence on corticosteroids.
Thankfully, in many cases, the answer is no. Blindness is often the end result of untreated or poorly treated uveitis. When disease is caught early enough, prior to complications, inflammation can usually be treated successfully with appropriate therapy.
However, when disease is not detected early enough, or when providers who are unfamiliar or uncomfortable dealing with uveitis fail to refer to a specialist, complications are much more prevalent and prognosis usually worse. Occasionally uveitis is severe and may lead to complications despite aggressive and timely therapy.