Uveitis: Eye Inflammation, Causes, and Steroid Therapy

Uveitis isn’t just a red eye. It’s inflammation deep inside your eye - in the uvea, the middle layer that feeds your retina and iris. Left untreated, it can blur your vision, cause permanent damage, and even lead to blindness. This isn’t rare. It’s the third leading cause of vision loss worldwide. If you’ve had sudden eye redness, pain when reading, or floaters that won’t go away, you need to know what’s happening - and what to do next.

What Exactly Is the Uvea?

The uvea isn’t one part. It’s three layers stacked together: the iris (the colored part), the ciliary body (which controls lens focus and fluid production), and the choroid (a blood-rich layer behind the retina). Together, they supply oxygen and nutrients to the eye’s most sensitive tissues. When inflammation hits any of these, it’s uveitis. The location determines the symptoms, severity, and treatment.

Four Types of Uveitis - And How They Feel

Uveitis isn’t one condition. It’s four, each with different signs and risks.

• Anterior uveitis (iritis) is the most common - about 75-90% of cases. It hits the front: iris and ciliary body. You’ll know it. Your eye turns blood-red. Light hurts. You can’t read without squinting. Pain is sharp, often worse when focusing. This type comes on fast - sometimes in hours. It usually affects one eye, but can spread.
• Intermediate uveitis (pars planitis) targets the vitreous, the jelly-like fluid behind the lens. Symptoms are subtler: floaters, blurred vision, no pain. It’s sneaky. People think it’s just tired eyes. But it often becomes chronic, lasting years with flare-ups. Macular edema - swelling in the center of your vision - is a big risk here.
• Posterior uveitis attacks the retina and choroid. This is the most dangerous. Vision loss happens slowly, often in both eyes. You might not notice until it’s advanced. It’s frequently diagnosed during a routine eye exam because symptoms don’t scream for attention. Retinal scarring and optic nerve damage are real threats.
• Panuveitis hits all layers at once. It’s the worst-case scenario. You get redness, pain, floaters, blurred vision - everything. It’s linked to serious autoimmune or infectious diseases. Recovery is harder, and complications are common.

What Causes Uveitis? Most Cases Have No Clear Answer

You’d think doctors could point to a virus, an injury, or a disease. But here’s the hard truth: in about half to two-thirds of cases, the cause is unknown. That’s idiopathic uveitis. No test finds it. No blood work explains it.

When there is a cause, it falls into three buckets:

• Autoimmune diseases: Ankylosing spondylitis, sarcoidosis, multiple sclerosis, lupus. Your immune system attacks your own eye tissue, thinking it’s foreign.
• Infections: Herpes simplex, shingles (herpes zoster), cytomegalovirus, syphilis, toxoplasmosis. These germs trigger inflammation as they try to hide in the eye.
• Trauma or surgery: A blow to the eye, a scratch, or even an eye operation can spark inflammation as the body tries to heal.

The Lions Eye Institute says uveitis is the eye’s response to tissue damage, germs, or toxins. But too often, the trigger just vanishes. That doesn’t make it less real. It just makes it harder to treat.

Steroid Therapy: The First Line of Defense

There’s no magic cure. But there’s one treatment that works across all types: steroids. Corticosteroids are powerful anti-inflammatories. They shut down the immune system’s overreaction in the eye.

How you get them depends on where the inflammation lives:

• Anterior uveitis: Eye drops. Prednisolone acetate 1% is standard. You might start with drops every hour, then taper over weeks. The goal? Kill inflammation fast, then stop before side effects start.
• Intermediate uveitis: Drops don’t reach deep enough. You need injections around the eye (periocular) or oral steroids like prednisone. Some patients get implants that slowly release steroids inside the eye for months.
• Posterior uveitis: Oral steroids are common. For severe cases, intravitreal implants (like Ozurdex) deliver steroids directly into the vitreous. This avoids whole-body exposure.
• Panuveitis: Usually requires systemic steroids - pills or IV - because the inflammation is everywhere.

The National Eye Institute says it plainly: “Uveitis can cause vision loss if you don’t treat it.” That’s why doctors push for quick action. Delay even a few days, and you risk scarring, glaucoma, or cataracts.

The Hidden Cost of Steroids

Steroids save vision - but they can hurt it too.

Long-term use, especially oral steroids, carries risks:

• Cataracts: Clouding of the lens. Happens in up to 40% of patients on long-term steroids.
• Steroid-induced glaucoma: Pressure builds inside the eye. If unchecked, it damages the optic nerve - permanently.
• Systemic side effects: Weight gain, mood swings, high blood sugar, bone thinning. These are real for people on pills for months.

That’s why treatment isn’t just about starting steroids. It’s about knowing when to stop - or switch.

For chronic or recurring uveitis, doctors turn to steroid-sparing drugs: methotrexate, mycophenolate, azathioprine. These slow the immune system without the steroid side effects. They take weeks to work, but they let you reduce or eliminate steroids over time.

When to See a Doctor - Right Now

You don’t need to wait for a routine checkup. If you have any of these, go to an eye specialist today:

• Sudden redness in one or both eyes
• Pain that gets worse when reading or focusing
• Floaters that won’t fade - especially if they multiply
• Blurred vision that doesn’t clear with glasses
• Extreme sensitivity to light - even indoors

The NHS notes that eye pain from uveitis often feels worse during reading. That’s a red flag. Prevent Blindness warns symptoms can get worse fast. Don’t assume it’s allergies or tiredness. Uveitis doesn’t wait.

What Happens If You Ignore It?

Untreated uveitis doesn’t just fade. It destroys.

- Adhesions: The iris sticks to the lens or retina. This distorts the pupil and blocks fluid flow, raising eye pressure.

- Macular edema: Swelling in the central retina. This blurs your ability to read, drive, or recognize faces.

- Glaucoma: Permanent nerve damage from high pressure.

- Cataracts: Clouded lenses from steroid use or inflammation.

- Retinal detachment: In posterior uveitis, inflammation can pull the retina loose.

- Permanent vision loss: Especially in posterior uveitis and panuveitis. Once the retina or optic nerve is scarred, vision won’t come back.

The Lions Eye Institute calls uveitis a “potentially sight-threatening problem.” That’s not fear-mongering. That’s medicine.

What to Expect at the Eye Doctor

Your ophthalmologist won’t just look in your eye. They’ll investigate.

- Slit-lamp exam: A microscope with bright light checks for cells and flare in the front of the eye.

- Retinal exam: Pupil dilation lets them see the back of the eye - retina, choroid, optic nerve.

- Eye pressure test: Glaucoma is a common complication.

- Blood tests: For syphilis, sarcoidosis, Lyme, TB - if they suspect an infection or autoimmune cause.

- Imaging: OCT scans show swelling in the macula. Fluorescein angiography checks blood flow in the retina.

There’s no single test for uveitis. Diagnosis is a puzzle - symptoms, exam findings, and sometimes ruling out everything else.

Can Uveitis Come Back?

Yes. Especially intermediate and posterior types. Some people have flare-ups every few months for years. That’s why long-term follow-up matters. Even if your eye looks fine, inflammation can be hiding.

Regular checkups every 3-6 months are common for chronic cases. Your doctor will monitor pressure, vision, and retinal health. If you notice symptoms returning - even mildly - don’t wait. Call your eye doctor.

Living With Uveitis

It’s not just about medicine. It’s about adaptation.

- Wear UV-blocking sunglasses. Light sensitivity doesn’t go away overnight.

- Avoid rubbing your eyes. Even gentle pressure can worsen inflammation.

- Keep your overall health in check. Autoimmune conditions like ankylosing spondylitis need management too.

- Talk to your doctor about steroid alternatives if you’re on pills long-term.

- Join a support group. Chronic uveitis is isolating. You’re not alone.

Vision recovery is possible - if treatment starts early. Many people with anterior uveitis regain full sight. But for those with posterior or chronic forms, the goal shifts: preserve what’s left. Prevent more loss.

Bottom Line

Uveitis is not a minor eye irritation. It’s a serious, sight-threatening inflammation that demands immediate attention. Steroids are your best tool - but only if used right, at the right time, and with the right follow-up. If you have redness, pain, floaters, or sudden blurred vision, don’t wait. Don’t guess. See an eye specialist now. Your vision isn’t something you can afford to risk.