Scleritis refers to an inflammatory condition affecting the sclera, the tough, white outer layer that provides structural integrity to the eyeball. While inflammation can occur in various parts of the eye, posterior scleritis specifically involves the rear portion of this protective layer. This distinct form of scleritis is less frequently encountered compared to its anterior counterpart, yet it often presents with greater severity and can pose significant challenges for diagnosis.
What is Posterior Scleritis?
Posterior scleritis is an inflammatory disorder that targets the posterior segment of the sclera, the opaque, fibrous outer coat of the eye. This inflammation often extends beyond the sclera, potentially involving adjacent ocular structures such as the choroid, retina, and the optic nerve. Unlike anterior scleritis, which affects the front of the eye and typically presents with noticeable redness and swelling, posterior scleritis is often hidden. Its deeper location means external signs like visible redness are usually absent, making diagnosis challenging without specialized examination. The condition involves an immune response that leads to tissue damage and swelling in the back of the eye.
Identifying the Symptoms
The symptoms of posterior scleritis can be varied and often lack specificity, contributing to diagnostic difficulty. These often include a deep, dull ache in the eye, which may radiate outwards to the surrounding head or face. Vision changes are common, ranging from blurred vision and double vision (diplopia) to more significant vision loss. Patients may also notice increased sensitivity to light (photophobia) and develop headaches. Unlike anterior scleritis, visible eye redness is typically absent, meaning the eye may appear normal externally despite internal inflammation.
Underlying Causes and Associated Conditions
Posterior scleritis can arise without a clear identifiable cause, in which case it is termed idiopathic. However, it is often linked to underlying systemic autoimmune or inflammatory diseases affecting other parts of the body. Common associated conditions include rheumatoid arthritis, a chronic inflammatory disorder primarily affecting joints, and systemic lupus erythematosus, a chronic autoimmune disease that can impact various organ systems. Other recognized associations include connective tissue diseases like granulomatosis with polyangiitis and other forms of vasculitis, which involve inflammation of blood vessels. Less frequently, posterior scleritis can stem from infectious agents, though this is a rarer etiology.
Diagnosis and Management Strategies
Diagnosis is necessary and includes a comprehensive ophthalmic examination, including indirect ophthalmoscopy to view the back of the eye. B-scan ultrasonography is a particularly valuable diagnostic tool, allowing clear visualization of thickened sclera, fluid accumulation, and other inflammatory changes in the posterior segment. Other imaging techniques like magnetic resonance imaging (MRI) or computed tomography (CT) scans can further assess inflammation and rule out other conditions.
Treatment primarily focuses on reducing inflammation and preserving vision. Systemic corticosteroids, administered orally or intravenously, are often the initial and most effective treatment to rapidly suppress the inflammatory response. For chronic or recurrent disease, or inadequate response to corticosteroids, immunosuppressive medications may be prescribed to modulate the immune system. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used for milder cases or as an adjunct therapy to manage pain and inflammation.
Potential Complications and Long-Term Outlook
If posterior scleritis remains undiagnosed or untreated, or if the inflammation is severe, it can lead to several serious ocular complications. These include significant vision loss, retinal detachment, where the light-sensitive retina pulls away from its supporting layers, and choroidal detachment, involving the vascular layer beneath the retina. Optic disc edema (swelling of the optic nerve head) is also possible. Persistent inflammation can contribute to secondary glaucoma (increased eye pressure) and cataracts (clouding of the lens).
Early and consistent treatment is important to prevent or minimize these adverse outcomes. With appropriate management, the prognosis for preserving vision is generally favorable, though the condition can recur, requiring ongoing monitoring and potential retreatment.