Ophthalmology
Sclera: Episcleritis and Scleritis
Sclera for MBBS and NEET-PG: episcleritis versus scleritis, phenylephrine blanching test, classification of scleritis and its systemic autoimmune links, mapped to NMC codes OP5.
MedNext Academy | 3 min read
Sclera: Episcleritis and Scleritis
Sclera for MBBS and NEET-PG: episcleritis versus scleritis, phenylephrine blanching test, classification of scleritis and its systemic autoimmune links, mapped to NMC codes OP5.
This chapter separates the two inflammations of the outer eye wall that examiners repeatedly contrast. It teaches the clinical distinction of the benign, painless episcleritis from the painful, potentially sight-threatening scleritis, the phenylephrine blanching test, the classification of scleritis, and its strong link to systemic autoimmune disease.
High-yield: Sclera: Episcleritis and Scleritis
- Episcleritis is inflammation of the superficial episcleral tissue, is usually benign and self-limiting, and causes mild redness with little or no pain.
- Scleritis is inflammation of the deep sclera, causes severe boring pain that wakes the patient at night, and can threaten vision.
- In episcleritis the redness blanches with topical phenylephrine, whereas the deep vascular plexus in scleritis does not blanch, which is a useful bedside distinction.
- The engorged vessels of episcleritis are superficial and can be moved with a cotton bud, unlike the fixed deep vessels of scleritis.
- Scleritis is far more likely than episcleritis to be associated with systemic disease, especially rheumatoid arthritis and granulomatosis with polyangiitis.
- Anterior scleritis is classified as diffuse, nodular or the sight-threatening necrotising type.
- Necrotising scleritis without inflammation is called scleromalacia perforans and is typically seen in long-standing rheumatoid arthritis.
- Posterior scleritis can mimic an orbital or retinal mass and may cause proptosis, disc swelling and exudative retinal detachment.
- The bluish hue of a thinned sclera reveals the underlying uvea, seen in scleromalacia perforans and in blue sclera of osteogenesis imperfecta.
- Episcleritis is usually managed with lubricants or a topical non-steroidal agent, as it settles on its own.
- Scleritis needs systemic non-steroidal anti-inflammatory drugs or oral steroids, and necrotising disease needs systemic immunosuppression.
- Any patient with scleritis should be screened for an underlying connective tissue or vasculitic disorder.
- A painless red eye with good vision favours episcleritis, while a painful red eye that disturbs sleep favours scleritis.
- Failure to recognise scleritis as a marker of systemic vasculitis can delay life-saving immunosuppression.
Episcleritis versus scleritis
- **Depth and pain:** Episcleritis is superficial with mild or no pain; scleritis is deep with severe boring pain.
- **Phenylephrine test:** Vessels blanch in episcleritis; deep vessels do not blanch in scleritis.
- **Systemic link:** Uncommon in episcleritis; common in scleritis (rheumatoid arthritis, vasculitis).
- **Treatment:** Episcleritis needs lubricants or topical NSAID; scleritis needs systemic NSAID, steroids or immunosuppression.
NMC competencies in this chapter
- **OP5.1:** Episcleritis: features and management
- **OP5.2:** Scleritis: features, classification and systemic associations
- **OP6.1:** Intraocular inflammation
- **OP6.2:** Acute and chronic iridocyclitis
- **OP4.3:** Corneal oedema
- **OP8.3:** Fundus examination technique and findings
Frequently Asked Questions
How do you tell episcleritis from scleritis?
Episcleritis is superficial, mildly red and painless or only mildly sore, and its vessels blanch with topical phenylephrine. Scleritis is deep, severely painful, disturbs sleep and its deep vessels do not blanch.
Why does scleritis matter systemically?
Scleritis is often the ocular marker of a systemic connective tissue or vasculitic disease such as rheumatoid arthritis or granulomatosis with polyangiitis, so it should prompt a search for the underlying condition.
What is scleromalacia perforans?
It is necrotising scleritis without overt inflammation, typically seen in long-standing rheumatoid arthritis, in which the sclera thins so that the underlying bluish uvea shows through.
How is each condition treated?
Episcleritis usually settles with lubricants or a topical anti-inflammatory agent. Scleritis requires systemic non-steroidal anti-inflammatory drugs or oral steroids, and necrotising disease needs systemic immunosuppression.
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