The episclera is the outermost layer of the sclera (which is the white portion of the eye), located beneath the conjunctiva. It is made of stromal tissue and attaches to Tenon’s capsule. It provides nutrition to the sclera as it is densely vascularised.
Episcleritis is benign and self-limiting usually.
Scleritis is always accompanied with overlying episcleritis but episcleritis is rarely associated with scleritis.
🏘 Epidemiology
Young and middle-aged adults as it is associated with rheumatoid arthritis and IBD and not infection.
😷 Presentation
It is usually acute onset and unilateral but about 50% of cases are bilateral so this is not a useful distinction.
- Red eye
- Not painful but there may be mild pain at most.
- Watery eye
- Photophobia may be present.
- Mobile episcleral vessels - these injected vessels are mobile when gentle pressure is applied on the sclera. With scleritis, the vessels are deeper and don’t move.
Phenylephrine drops may be used to differentiate between episcleritis and scleritis as it blanches the episcleral vessels (due to vasoconstriction) but not the scleral vessels.
- If the eye blanches after phenlyephrine drops → episcleritis is the diagnosis. If not → scleritis is considered the diagnosis.
🧰 Management
It is self-limiting and will resolve in 1-4 weeks.
Artificial tears may be beneficial and in more severe cases NSAIDs or topical steroids.
Analgesia, cold compression and safety netting is sufficient.