Uveitis: Eye Inflammation, Causes, and Steroid Therapy

Uveitis is not just a red eye. It’s a serious inflammation deep inside the eye that can steal your vision-sometimes without warning. If you’ve noticed sudden eye pain, blurry vision, or floaters that won’t go away, this isn’t something to brush off. Uveitis affects the uvea, the middle layer of your eye that includes the iris, ciliary body, and choroid. This layer feeds blood to key parts of your eye, and when it swells, it doesn’t just hurt-it can damage your retina, lens, or optic nerve. Left untreated, uveitis becomes one of the top three causes of blindness worldwide.

What Exactly Is the Uvea?

The uvea isn’t one single part. It’s three layers stacked together. The front part, the iris, controls how much light enters your eye. Behind it is the ciliary body, which helps focus your lens and makes the fluid inside your eye. The back part, the choroid, is packed with blood vessels that feed the retina. When inflammation hits any of these, it’s uveitis. The location of the inflammation determines the type, symptoms, and how it’s treated.

The Four Types of Uveitis

Not all uveitis is the same. Doctors classify it by where the swelling happens:

• Anterior uveitis (iritis) is the most common-making up 75% to 90% of cases. It hits the front, near the iris. Symptoms show up fast: red eye, sharp pain, light sensitivity, and blurred vision. You might notice it when reading, because focusing strains the inflamed iris. This type usually responds well to eye drops.
• Intermediate uveitis (pars planitis) affects the vitreous, the jelly-like fluid in the center of the eye. It’s less painful but causes floaters-those dark spots or squiggles drifting across your vision-and blurry sight. It often lasts longer, sometimes years, and can lead to swelling in the macula, the part of the retina that gives you sharp central vision.
• Posterior uveitis attacks the choroid and retina at the back of the eye. This is the most dangerous form. It often affects both eyes and develops slowly, so you might not notice until your vision is already fading. It’s the main cause of permanent vision loss in uveitis patients.
• Panuveitis means all layers are inflamed. It combines symptoms from all the others: pain, floaters, blurred vision, and severe swelling. It’s rare but the most serious.

Acute uveitis lasts less than six weeks. Chronic uveitis sticks around longer and can flare up again and again. The longer inflammation goes untreated, the more damage it does to your eye’s structure.

What Causes Uveitis?

Here’s the tricky part: doctors can’t find a clear cause in about one-third of cases. That’s called idiopathic uveitis. But when they can, the triggers fall into three big groups.

• Autoimmune diseases: Your immune system attacks your own eye tissue. Conditions like ankylosing spondylitis, sarcoidosis, multiple sclerosis, and rheumatoid arthritis are common culprits. If you have one of these, your eye inflammation might be a sign your body is out of balance.
• Infections: Viruses like herpes simplex or shingles (herpes zoster), bacteria like syphilis, or parasites like toxoplasmosis can spread to the eye. Even fungal infections like histoplasmosis-common in certain parts of the U.S.-can trigger uveitis.
• Eye trauma or surgery: A scratch, a blow to the eye, or even recent eye surgery can spark inflammation. Sometimes, the body overreacts to the injury.

It’s not just about what’s in your eye. Uveitis is often a signal that something deeper is going on in your body. That’s why your eye doctor might send you to a rheumatologist or infectious disease specialist.

Steroid Therapy: The First-Line Treatment

Steroids are the backbone of uveitis treatment. They work fast to calm inflammation and prevent permanent damage. But how you get them depends on where the inflammation lives.

• Anterior uveitis: Steroid eye drops-like prednisolone acetate 1%-are the go-to. You’ll start with drops every hour or two, then taper down over weeks as the swelling fades. Sometimes, a dilating drop is added to keep the iris from sticking to the lens.
• Intermediate uveitis: Eye drops don’t reach far enough. Doctors often use injections around the eye (periocular) or implant tiny steroid devices inside the eye (intravitreal). Oral steroids may be needed if it’s severe or recurrent.
• Posterior uveitis: This needs strong, systemic treatment. Oral prednisone is common, sometimes with other immunosuppressants. Injections or implants are used if the inflammation is focused on the retina.
• Panuveitis: Usually requires oral steroids plus close monitoring. Some patients need long-term immunosuppressants to avoid constant steroid use.

Timing matters. The sooner you start steroids after symptoms appear, the better your chances of saving your vision. Delaying treatment even a few days can mean irreversible damage to your retina or optic nerve.

The Dark Side of Steroids

Steroids work-but they come with risks. Long-term use can cause cataracts, where your lens clouds over. It can also raise pressure inside your eye, leading to steroid-induced glaucoma. About 30-40% of people on long-term oral steroids develop one or both of these problems.

This is why doctors don’t just give steroids and walk away. They monitor eye pressure every few weeks. They check for cataracts with regular scans. And if uveitis keeps coming back, they switch to steroid-sparing drugs-medicines like methotrexate, mycophenolate, or anti-TNF biologics-that control inflammation without the side effects. These take longer to work, but they’re safer for the long haul.

When to See a Doctor

If you have any of these symptoms, don’t wait:

• Sudden red eye with pain
• Blurred vision that doesn’t clear up
• Floaters that multiply or get worse
• Extreme sensitivity to light
• Vision loss in one or both eyes

Uveitis is not like a cold. It doesn’t go away on its own. Even if symptoms fade, the inflammation might still be there, quietly damaging your eye. A routine eye exam can catch posterior uveitis before you even notice a problem.

What Happens If It’s Not Treated?

Untreated uveitis doesn’t just cause blurry vision. It leads to:

• Macular edema: Fluid builds up in the central retina, blurring your ability to read or recognize faces.
• Synechiae: The iris sticks to the lens or cornea, changing your pupil shape and blocking fluid flow-this can raise eye pressure and cause glaucoma.
• Cataracts: Clouding of the lens from chronic inflammation or steroid use.
• Glaucoma: High pressure inside the eye damages the optic nerve.
• Retinal detachment: Inflammation weakens the retina, causing it to peel away.
• Permanent vision loss: Especially in posterior uveitis and panuveitis.

Once this damage happens, it’s often irreversible. That’s why uveitis is treated like an emergency-even if the pain fades.

Living With Chronic Uveitis

If your uveitis is chronic, you’ll need ongoing care. Regular eye exams every 3-6 months are standard. You might need blood tests to check for underlying autoimmune disease. Some patients learn to recognize early signs of a flare-like a slight increase in floaters-and call their doctor before symptoms get bad.

Managing stress, quitting smoking, and keeping other health conditions (like high blood pressure or diabetes) under control can help reduce flare-ups. There’s no cure, but with the right treatment plan, most people keep good vision for life.