What is the Episclera?
The episclera is a fibroelastic structure consisting of two layers joined together loosely. It is the white of the eye. The outer parietal layer, with the vessels of the superficial episcleral capillary plexus, is the more superficial layer. The superficial vessels appear straight and are arranged radially. The deeper visceral layer contains a highly connected network of vessels.
Both vessel networks originate from the anterior ciliary arteries, which stem from the muscular branches of the ophthalmic artery. The episclera lies between the superficial scleral stroma and Tenon’s capsule.
- Episclera is a fibroelastic structure between the sclera and Tenon’s capsule.
- Inflammation of the episcleral can be of unknown cause or from systemic disease.
- Episcleritis may resolve on its own or require treatment.
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Understanding the Episclera
The episclera is a layer of the eye that can be affected by acute, unilateral, or bilateral inflammation called episcleritis. Episcleritis can be diffuse, sectoral, or nodular, and is most often idiopathic (cause unknown), but can also be associated with systemic conditions and infections. Nodular episcleritis is classified by a small, elevated area of inflamed episcleral tissue. In simple episcleritis, vascular congestion is present in the absence of an obvious nodule.
The majority of episcleritis cases are idiopathic, but 26% to 36% of patients have cases associated with a systemic disease. The following systemic conditions may cause episcleritis: Rheumatoid arthritis, Crohn disease, ulcerative colitis, psoriatic arthritis, systemic lupus erythematosus, reactive arthritis, relapsing polychondritis, ankylosing spondylitis, polyarteritis nodosa, Behcet’s disease, Cogan syndrome, and granulomatosis with polyangiitis, formerly called Wegener granulomatosis.
If the episclera is inflamed, symptoms may include:
- Sectoral or diffuse redness
- Mild ocular discomfort
- Normal vision
Risk Factors for Episclera Inflammation
Episcleritis is most diagnosed in young to middle-aged females and is rarely diagnosed in children. The incidence and prevalence of episcleritis are higher in populations with collagen-vascular and autoimmune disease.
Diagnosing Episclera Inflammation
Episcleral inflammation is diagnosed by an eye doctor. They can view the episclera through the slit lamp. When a systemic condition is suspected, blood work or imaging may be performed to confirm systemic diagnosis.
Most cases of episcleritis are mild and will resolve without treatment within 2 to 21 days. Supportive treatment may include refrigerated artificial tears at least four times daily. Some patients may require medical treatment depending on the severity of their symptoms. For those patients who need treatment, a mild topical corticosteroid such as fluorometholone 0.1% or loteprednol etabonate 0.5% may be prescribed four times a day for 1 to 2 weeks then tapered. Oral NSAIDs such as ibuprofen or naproxen may be used as an alternative to topical steroids.