Scleritis is an inflammatory condition of the sclera, the white, protective outer layer of the eyeball. This inflammation can cause permanent damage and vision loss if not addressed promptly. It is distinct from more common causes of eye redness, like conjunctivitis, because it affects deeper tissue and is associated with significant pain. The condition necessitates immediate medical evaluation.
Recognizing the Symptoms
The most prominent symptom of scleritis is a deep, severe, and boring ache in the eye. This pain is intense enough to interfere with sleep and can radiate to the jaw, face, or head. Movement of the eye can make the pain worse. Accompanying this discomfort is a distinct redness of the sclera, which can appear purplish or bluish.
The presentation of symptoms can vary depending on the location of the inflammation. Scleritis is categorized into anterior, affecting the front of the eye, and posterior, affecting the back. Anterior scleritis, the more common form, involves visible redness and swelling. Posterior scleritis is rarer and may present with less obvious external redness but is more likely to cause issues like floaters or decreased vision.
It is helpful to distinguish scleritis from episcleritis, another inflammatory eye condition. Episcleritis involves the more superficial tissue layer between the sclera and the conjunctiva. While it also causes redness, the color is a brighter red, and the primary sensation is irritation or discomfort rather than the deep, severe pain characteristic of scleritis. This distinction is important for diagnosis and management.
Underlying Causes and Risk Factors
In approximately half of all cases, scleritis is a manifestation of a systemic autoimmune or inflammatory disorder. These conditions involve the body’s immune system attacking its own tissues, and the sclera can be a target. The onset of scleritis can be the first sign of a previously undiagnosed systemic disease.
Rheumatoid arthritis is one of the most frequently associated autoimmune conditions. Other diseases linked to scleritis include:
- Lupus
- Inflammatory bowel disease (Crohn’s disease and ulcerative colitis)
- Granulomatosis with polyangiitis
- Scleroderma
- Sjogren’s syndrome
The inflammation seen in scleritis often reflects the disease activity occurring elsewhere in the body.
Less commonly, other factors can trigger scleritis. Infections from bacteria, fungi, or viruses can lead to an inflammatory response in the sclera. In rare instances, physical trauma to the eye, including surgical complications, can be a cause. Identifying whether the cause is autoimmune or infectious is fundamental to determining the correct treatment.
The Diagnostic Process
An ophthalmologist diagnoses scleritis through a detailed eye examination. The process includes a review of the patient’s symptoms and a visual acuity test. A slit-lamp examination is a main component of the diagnosis, as this microscope allows the doctor to view the eye’s structures and determine the depth of the inflammation.
To differentiate scleritis from the less severe episcleritis, a doctor may administer a phenylephrine eye drop. This drop causes blood vessels in the superficial episcleral layer to constrict and whiten, a reaction known as blanching. In scleritis, the deeper vessels are affected and will not blanch, allowing for a clear diagnostic distinction.
If posterior scleritis is suspected, further imaging is required. A B-scan ultrasound or a CT scan can provide images of the back of the eye to confirm inflammation of the posterior sclera. Because of the strong link to systemic diseases, blood tests are performed to look for inflammatory markers and specific antibodies that can help identify an underlying autoimmune condition.
Medical Treatments for Scleritis
Treatment for non-infectious scleritis is aimed at controlling inflammation to alleviate pain and prevent eye damage. The approach is tiered, and the first line of therapy involves high-dose oral nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce swelling and pain.
If NSAIDs prove insufficient or if the scleritis is severe, the next step is systemic corticosteroids, such as prednisone. These are powerful anti-inflammatory agents that can manage more aggressive cases and bring the inflammation under control quickly.
For cases that are severe, recurrent, or necrotizing, or when a significant autoimmune disease is present, immunosuppressive or immunomodulatory drugs are used. Medications like methotrexate or mycophenolate mofetil work by moderating the immune response. Should an infection be the cause, treatment will focus on targeted antimicrobial medications to eliminate the specific pathogen.