Uveitis - Introduction
Uveitis is inflammation of any part of the uvea and is classified by the part of uvea that is inflamed.
Anterior Uveitis affects the front of the eye. It is often called iritis because it mainly affects the area around the eye’s iris. Anterior uveitis is the most common kind of uveitis making up 40-70% of all uveitis. It is usually acute (i.e. comes on suddenly and lasts for less than six weeks) and is associated with pain, light sensitivity and redness.
Intermediate Uveitis is inflammation of the ciliary body, the front end of the retina, and the vitreous. Intermediate uveitis is the least common type of uveitis, making up only 7-15% of cases. It is also known as cyclitis, pars planitis or vitritis. In most of the cases, the cause is unknown. Symptoms include floaters and blurred vision. People with intermediate uveitis are more likely to have chronic inflammation.
Normal Eye Anatomy
Anatomy of UVEA
The Uvea is the middle layer of the eyeball. The eye is made of three layers. The outermost is the sclera and cornea which keep the contents intact and maintain its shape. The inner layer is the retina which is highly sophisticated neural tissue and forms the image that is sent to the brain via the optic nerve. The middle layer is the uvea and is responsible for the ‘housekeeping’ of the eye. It carries the blood vessels, nerves, pigment cells and immune cells. It extends from the front to the back of the eye and at different parts is called differently. In the front is the Iris and anterior part of the ciliary body (anterior uvea), in the middle is the posterior part of the ciliary body (pars plana) (intermediate uvea) and posteriorly it is called the choroid.
Symptoms of Uveitis
The symptoms depend on the location of the uveitis. Anterior uveitis usually presents as a painful, red eye with mild blurring of vision. In intermediate and posterior uveitis, the eye is not so painful but the patient sees multiple small floaters (like a dust storm) with or without blurring or severe loss of vision.
Causes of Uveitis
Uveitis is inflammation of the uvea. Inflammation is the body’s response to injury, or trauma. To treat uveitis, doctors look for the cause of the trauma to the eye however in the majority of cases a cause (as many as a third or half of all uveitis) cannot be found. It is then believed that there may be an abnormal triggering of the body’s immune system causing the uveitis (autoimmune diseases).Many times the underlying condition may not be symptomatic & eye may be first organ to be affected.
Amongst the known causes uveitis can be caused by different kinds of organisms, including a virus, bacteria , parasites or rarely fungus. Genes can play an important role in uveitis.
Causes of Anterior Uveitis
In more than a third of all cases of anterior uveitis, the exact cause is unknown.
Causes may include :
Ankylosing Spondylitis : It is a type of arthritis that mainly affects the spine. This can cause recurrent arthritis and prompt referral to orthopedic specialist can prevent permanent changes.
Reiter’s Syndrome is an inflammatory arthritis common in young men – often caused by Chlamydia infection.
Psoriatic Arthropathy is a form of arthritis that nearly a quarter of people with psoriasis may develop. It causes pain, swelling and stiffness in joints. Psoriasis is an immune-related disease of the skin and joints.
Inflammatory Bowel Disease causes inflammation, ulcers and scarring to the wall of the intestine but can affect other parts of the body as well.
Juvenile Rheumatoid Arthritis (JRA) is a kind of arthritis (inflammation of the joints) in children. Uveitis is the most common eye problem that can develop in children with JRA. Children with JRA may get uveitis before JRA is even diagnosed, or it can occur many years later. It may remain asymptomatic and all such children should be screened for uveitis 6 monthly.
Herpes is a common viral infection that causes oral or genital herpes. It mostly affects only one eye, but it can cause recurrent uveitis.
Sarcoidosis is a systemic Autoimmune disease which mainly affects the Lungs, joints, skin eyes etc. Uveitis may be the first symptom in these people
Fuch’s Heterochromic Iridocyclitis is a chronic kind of iritis. Its cause is unknown.
Systemic Lupus Erythematosis is a chronic inflammatory disease that affects different parts of the body, including the skin, joints, blood, and kidneys and is related to the body’s immune system.
Intraocular lens surgically implanted to replace a cataract lens. Uveitis can be caused by trauma related to cataract surgery. In cataract surgery, the eye’s natural lens is removed and replaced with an artificial (plastic) lens. The presence of this artificial lens can cause anterior uveitis.
Posner-Schlossman Syndrome (PSS) is an uncommon inflammatory eye condition that usually affects one eye at a time. It typically affects young to middle-aged adults who develop high pressure inside the eye and mild inflammation.
Rheumatoid Arthritis is a chronic inflammation of the joints that can cause permanent joint damage and disability.
Syphilis is a sexually transmitted disease. It can be cured, but if left untreated, the late stages of the disease can cause heart problems, abnormalities, mental illness, blindness and death. Although on the decline over the past decade, it has seen more cases in recent years.
Tuberculosis (TB) is a disease caused by bacteria that usually attacks the lungs. It is spread through the air from one person to another and is rampant in our country. Ocular Tuberculosis is hypersensitivity reaction to the tubercular organism and patients may be healthy with no respiratory symptoms.
Lyme Disease is a disease caused by bacteria that are transmitted to people from the bite of a deer tick. It often causes a "bull's-eye" rash around the bite, with symptoms such as fever, tiredness, headache, muscle and joint aches.
Causes of Intermediate Uveitis
In more than two thirds of all cases of intermediate uveitis, the exact cause is unknown.
The remaining third of all cases are thought to be caused by conditions such as :
Sarcoidosis : MS (multiple Sclerosis) an inflammatory disease that affects the brain and spinal cord and it may symptomatic in the initially.
Lyme Disease : Tuberculosis and Syphilis can cause all types of uveitis. In our country they need to be looked for in all patients with uveitis.
Panuveitis : Panuveitis is inflammation of all the parts of the uvea and is a serious disorder.
Intermediate Uveitis with KP's
Causes of Posterior Uveitis
Following is a list of common causes of posterior uveitis. In more than one in ten cases of uveitis, however, the exact cause is unknown.
Oxoplasmosis is an infection caused by a parasite. People may become infected from eating raw or undercooked meats, drinking unpasteurized milk, cleaning cat litter boxes, or working in gardens or playing in sandboxes that contain cat feces.
Serpiginous Choroidopathy is related to uveitis – a rare condition that affects the part of the uvea called the choroid. It can affect the vitreous body and cause lesions on the retina that result in vision loss.
Tuberculosis can cause inflammations of the blood vessels, choroiditis and abscesses.
Cytomegalovirus Retinitis (CMV Retinitis) is a serious eye infection of the retina. It is a threat to people with weak immune systems, such as people with HIV, people undergoing chemotherapy, and people who have had organ transplants. Without treatment, CMV retinitis can destroy the retina and damage the optic nerve, resulting in blindness.
Birdshot Retinochoroidopathy may be an autoimmune disease. People with this condition may experience blurred vision, sensitivity to light, floaters, and night blindness. In most people it affects both eyes. It causes white or yellow lesions scattered around the retina that can damage the retina and affect the vitreous.
Acute Retinal Necrosis is a condition that often causes retinal detachment and vision loss. Signs may include red eyes, eye pain and hazy/blurred vision. It is generally caused by Herpes virus.
Behcet’s Disease is a rare, chronic inflammatory disease. The cause of Behcet's disease is unknown. If often begins when individuals are in their 20s or 30s, although it can happen at any age. Uveitis is very common with people suffering from Behcet’s, which can cause acute uveitis that happens soon after onset of Behcet’s disease.
Syphilis is a sexually transmitted disease. It can be cured, but if left untreated, the late stages of the disease can cause heart problems, abnormalities, mental illness, blindness and death. Although on the decline over the past decade, more cases are being seen in recent years.
APMPPE is an eye condition that can cause temporary loss of vision related to lesions that appear in part of the retina. The lesions usually heal after a few weeks.