I talk a lot on this channel about inflammation of the external eye as in dry eye disease, but did you know that you can have inflammation INSIDE your eye as well?
Uveitis occurs when internal structures in the eye become inflamed. It’s a fascinating disease with many causes but can also be very serious, even causing blindness. And today, I’ll teach you all about it! You’ve made it to Eye School with me, Dr. D. Welcome! Make yourself comfy, and get ready to learn about Uveitis.
Let’s talk about Uveitis. Before we get started, to understand what's happening in Uveitis it’s critical to have an understanding of Ocular Anatomy, specifically the UVEA of the eye. The Uvea is located in what you could call the middle of the eye. It’s made up of three different structures. The first, you’re probably quite familiar with: it’s the iris, or the thin disc-like “colored” part of your eye. The iris regulates the amount of light entering the eye. I talk about that more in my pupil dilation video which I will link here.
The second part of your uvea is called the ciliary body. You may not have heard of this part of your eye, but behind the scenes the ciliary body is doing the hard work of regulating your eye pressure, holding your lens in place with zonules, and helping your eye focus from distance to near. Learn more about what happens when you stop being able to focus at near in this video.
The ciliary body can’t be seen without special lenses because it is located behind the sclera, or the white part of the eye. It surrounds the iris and extends 360 degrees around your eyeball. This lens is called a “4 mirror” and is what I use to examine the angle of the eye in the clinic. The anterior chamber angle represents where the iris and ciliary body meet and it gives important information about the health of the ocular drainage system but is also helpful when examining patients with uveitis. Finally, the choroid is the third part of the Uvea. The choroid is located between the densely fibrous outer scleral and the retina. It provides blood flow to the retina and is critical for ocular health.
What Uveitis Is In Detail
Uveitis refers to inflammation within the uveal tract. Any of the above structures can be affected, or they can all be affected! If JUST the iris is inflamed, the condition is called “iritis” while if the iris and ciliary body are both inflamed, we call that anterior uveitis. There’s a condition where just the section between the iris and the choroid are inflamed, and we call that “pars planitis.” When the choroid, or posterior aspect of the eye is inflamed that is called choroiditis. Finally, if the entire uveal tract is involved, we call that panuveitis. Anterior Uveitis is by far the most common of these conditions, accounting for 80-85% of uveitis.
Anterior uveitis causes a red painful eye, often with the redness concentrated around the iris in a circle. In addition, light sensitivity and blurred vision are common. Posterior uveitis symptoms can be more subtle, presenting as blurred vision or light sensitivity.
So what in the world causes these types of problems within the eye? Well, there are MANY MANY causes.
Iritis, or an inflammation of the iris can be caused by trauma. Recently in my clinic I saw a case of traumatic iritis after a direct hit to the eye while using a weed eater.
Anterior Uveitis can also be due to an inherited condition. Up to 50% of acute anterior uveitis cases are associated with human leukocyte antigen 27, which is more common in men than women and usually occurs between 20-40 years of age. HLAB-27 is also associated with Psoriasis, Ankylosing Spondylitis, Reactive Arthritis and IBD.
Autoimmune diseases like SLE and Sarcoidosis, rheumatoid arthritis and ankylosing spondylitis can also cause anterior or posterior uveitis. Control of the systemic condition often helps with control of the ocular inflammatory response, and many patients require steroid sparing immunosuppressive therapies like methotrexate, plaquenil, humira or others to control the inflammation.
All types of uveitis can also be due to infectious causes. Aids, Herpes, Syphilis, Tuberculosis, Histoplasmosis and Toxoplasmosis are all pathogens that can cause uveitis to occur in any one of the anatomical parts of the uvea that I mentioned before. With these types of infections, appropriate infectious disease treatment ranging from antibiotics to HAART THERAPY for HIV/aids or even antifungals may be necessary.
How Uveitis And Iritis Are Diagnosed and Treated
How does your doctor decide when to pursue lab testing?
It’s largely dependent on presentation and history. For instance, a mild unilateral anterior uveitis that has never recurred probably won’t warrant testing. A bilateral anterior presentation, a posterior presentation whether unilateral or bilateral, or even a unilateral presentation that is severe may prompt your doctor to write a lab order. Furthermore, observing the subtleties of the inflammatory response can be incredibly helpful in directing your testing. There is a characteristic “mutton fat” or greasy appearance to the inflammation that occurs in a granulomatous type of uveitis and those types of reactions only occur with a few of the possible causes that I have mentioned above.
How does uveitis affect the eye?
Anterior uveitis typically presents as a red painful eye that is light sensitive and may show a loss of vision as well. Left untreated, the inflammation can cause some problems within the eye. Inflammation tends to be sticky, and in the anterior part of the eye, it can cause a person's iris to stick backward to their lens, or forward to their cornea.
Uveitis can cause cataracts, fluid in the retina, even glaucoma, retinal detachment and loss of vision.
How do we treat it?
Anterior Uveitis is typically treated using topical steroid drops, dilation drops to help with the pain and dark glasses. Intermediate and posterior uveitis are treated using a combination of oral steroids, injected steroids and systemic therapy often with the assistance of other specialists like rheumatology.
Anterior uveitis will typically go away within a few days with treatment. Uveitis that affects the back of the eye, or posterior uveitis, typically heals more slowly than uveitis that affects the front of the eye. Relapses are common.
Posterior uveitis due to another condition may last for months and can cause permanent vision damage.
If you’ve had Uveitis in the past or currently, feel free to share your experience and encouragement for others in the comments below. This particular eye condition is a lesser known cause of pink eye but causes significant disruption and pain, so let’s give each other some encouragement here in the Eye School community. Today’s fun fact is: The uvea has 3 parts!