Scleritis is inflammation of the sclera, the tough white outer wall of your eye. It causes deep, boring eye pain that often worsens at night and with eye movement, and it can threaten your vision if left untreated. The condition is uncommon, affecting roughly 1 to 3 people per 100,000 each year, but it’s serious enough to require prompt treatment.
What Scleritis Feels Like
The hallmark of scleritis is severe, piercing eye pain. Unlike the mild irritation of a red eye from allergies or dryness, scleritis pain runs deep. It can wake you from sleep, radiate into your jaw, forehead, or temple, and get noticeably worse when you move your eyes. Many people also develop sensitivity to light.
The affected eye typically looks red, but the redness has a distinctive quality. Instead of the bright red of a surface irritation, scleritis produces a deeper blue-violet hue that’s easiest to see in natural daylight. The eye may also feel tender to the touch.
There is one exception to the pain rule. A form called scleromalacia perforans causes the sclera to thin severely, sometimes to the point of developing holes, yet it may produce little or no pain. This form typically occurs in people with longstanding rheumatoid arthritis.
Types of Scleritis
Scleritis is classified by where it occurs and how it behaves. About 98% of cases are anterior scleritis, meaning the inflammation is in the front portion of the eye. Anterior scleritis breaks down further into several patterns:
- Diffuse: Widespread inflammation across a broad area of the sclera. This is the most common and generally mildest form.
- Nodular: One or more firm, tender bumps form on the scleral surface.
- Necrotizing with inflammation: The most severe form. Intense pain accompanies destruction of scleral tissue, which can thin the eye wall and expose deeper layers.
- Necrotizing without inflammation (scleromalacia perforans): Painless but dangerous thinning of the sclera.
Posterior scleritis affects the back of the eye and is harder to detect because the inflammation isn’t visible on a standard exam. It can cause swelling of the retina, fluid buildup under the retina, and optic nerve problems. Doctors diagnose it primarily with ultrasound imaging. A characteristic finding called the “T-sign,” where fluid collects in the space between the optic nerve and the sclera, is considered definitive for posterior scleritis.
Scleritis vs. Episcleritis
These two conditions look similar on the surface but differ significantly. Episcleritis inflames only the thin tissue layer sitting on top of the sclera. It causes localized redness but no real eye pain, no light sensitivity, and it typically resolves on its own. Scleritis involves the sclera itself, hurts considerably, and needs treatment. If you have a red eye with deep pain that disrupts your sleep, that distinction matters.
What Causes It
In most cases, scleritis is driven by the immune system attacking the body’s own tissues. Up to half of people with scleritis have an underlying autoimmune condition. Rheumatoid arthritis is the single most common association, found in about 7% of scleritis patients. Granulomatosis with polyangiitis, a condition that inflames blood vessels throughout the body, has one of the strongest links to scleritis among autoimmune diseases. Lupus, inflammatory bowel disease, and other connective tissue disorders can also be underlying drivers.
A smaller number of cases are caused by infection. The most common infectious culprit in developed countries is Pseudomonas, a bacterium. Staph infections, tuberculosis, and fungal organisms like Aspergillus and Nocardia can also cause it. People exposed to agricultural soil or plant material face higher risk for certain fungal causes. Viral infections, particularly herpes simplex and varicella-zoster (the shingles virus), can trigger scleritis as well. Infectious scleritis sometimes follows eye surgery or eye trauma.
How It Affects Vision
Scleritis carries a real risk of vision loss. Studies estimate that 30 to 50% of people with scleritis experience some degree of decreased vision. The risk depends heavily on the type and whether the inflammation spreads to other structures inside the eye.
When scleritis triggers inflammation inside the eye (a combination doctors call scleritis with intraocular inflammation), outcomes are significantly worse. Patients in this group develop posterior complications at much higher rates, about 50% of eyes compared to roughly 12% of eyes with scleritis alone. Their vision tends to be worse at diagnosis and stays worse over time. Common complications include cataracts, glaucoma, swelling in the central retina, fluid detaching the retina, and optic nerve damage. In severe necrotizing cases, the sclera can thin enough to require surgical patching.
How It’s Diagnosed
An eye doctor can often identify anterior scleritis during a clinical exam using a slit lamp, a specialized microscope that illuminates the eye’s layers. The deep blue-violet color of inflamed scleral vessels helps distinguish it from episcleritis. For posterior scleritis, ultrasound imaging of the eye is the primary diagnostic tool, revealing thickened eye wall tissue, fluid pockets, or the characteristic T-sign near the optic nerve.
Because scleritis so often signals an underlying systemic disease, most patients will also get blood work and possibly imaging to screen for autoimmune conditions or infections. Identifying and treating the root cause is essential for preventing recurrence.
Treatment Approaches
Treatment depends on how severe the inflammation is and whether an underlying condition is driving it. Mild to moderate cases of non-necrotizing scleritis typically start with oral anti-inflammatory medications. If those aren’t enough, oral corticosteroids are the next step, often bringing relief relatively quickly.
For necrotizing scleritis or cases that keep relapsing, stronger immune-suppressing medications become necessary. These work by dialing down the overactive immune response that’s attacking the sclera. When standard immunosuppressants fail, biologic therapies offer another option. TNF inhibitors can control scleral inflammation within weeks. For cases that resist even those, drugs that target B cells (a type of immune cell) have shown effectiveness over six-month treatment periods. Newer biologic agents targeting other parts of the immune system, including those that block specific inflammatory signaling molecules, have also shown promise for stubborn cases.
Infectious scleritis requires a fundamentally different approach: targeted antibiotics, antifungals, or antivirals depending on the organism. Using immune-suppressing drugs in an infectious case can make things dramatically worse, which is why pinpointing the cause matters so much.
Treatment for scleritis is often long-term. The condition tends to recur, especially when linked to an autoimmune disease, and many people need ongoing medication to keep inflammation in check and protect their vision.