Episcleritis

Definition/diagnostic criteria Episcleritis is an inflammatory condition affecting the episclera, the thin layer of tissue between the conjunctiva and the sclera. It is characterised by sudden onset of redness and discomfort in the affected eye, without significant pain or visual impairment.

Epidemiology Episcleritis predominantly affects young and middle-aged adults and is more common in females. The exact prevalence in the UK is unknown, but it is considered a relatively common condition in primary care and ophthalmic practice. Associations with systemic autoimmune diseases are recognised, but most cases are idiopathic.

Diagnosis
Clinical features: The primary symptom of episcleritis is redness of the eye, often localised to one sector. Patients may report mild discomfort but not severe pain. There might be mild tearing but no discharge. Visual acuity is usually unaffected. It is important to differentiate episcleritis from scleritis, which is more severe and potentially sight threatening.

Investigations: Diagnosis is primarily clinical. Examination will reveal localised or diffuse vascular engorgement of the episcleral vessels. In more severe cases, there may be oedema of the episcleral tissue. If an underlying systemic condition is suspected, blood tests such as full blood count, ESR, CRP and autoantibodies may be indicated.

Treatment Treatment of episcleritis is largely symptomatic. Mild cases may require no treatment other than reassurance. For more bothersome symptoms, topical lubricants can provide relief. Topical anti-inflammatory agents, such as non-steroidal anti-inflammatory eye drops, can be used for more significant discomfort.

In cases that do not respond to topical treatment, a short course of oral NSAIDs may be considered. The use of corticosteroid eye drops should be reserved for severe cases and undertaken under ophthalmological supervision. Treatment of any underlying systemic disease is also essential.

Prognosis The prognosis for episcleritis is generally good. Most episodes resolve spontaneously within 1-3 weeks without any residual effect on vision. Recurrences are common but typically do not signify a serious underlying condition. Chronic episcleritis or cases associated with systemic diseases may require more prolonged management.