Episcleritis

Infections and Inflammations of the Sclera and Episclera

  • Sclera: tough, outer fibrous coat. Problems are very rare but can be potentially blinding and require urgent referall.

  • Episclera: Relatively thin layer of vascular connective tissue that lines the outermost layer of the sclera. Problems in the episclera are relatively quite common.

Episcleritis

  • Definition: Inflammation of the episclera, the space between the sclera and the conjunctiva, involving the episclera and Tenon's capsule.

  • Commonality: A prevalent condition that is typically benign, self-limiting, and potentially recurrent. It is non-sight threatening.

  • Demographics: Most commonly affects young adults to middle-aged individuals, with a higher prevalence in women.

  • Symptoms: Can be asymptomatic or present with tenderness in the affected area. Presents as a sectorial, diffuse (more common) or nodular redness under the conjunctiva, typically near the limbus (usually unilateral)

  • Etiology: Most cases are idiopathic; some have associations with collagen vascular diseases such as:

    • Rheumatoid arthritis

    • Polyarteritis nodosa

    • Systemic lupus erythematosus (SLE)

    • Gout

    • Herpes zoster ophthalmicus (HZO)

Main Presentations of Episcleritis

  1. Simple Sectorial Episcleritis: sector of redness within the eye. Most common form of Episcleritis.

  2. Simple Diffuse Episcleritis: redness is more generalised across the eye.

  1. Nodular Episcleritis: redness enlarges into a raised nodule in the episclera. Least common form.

Simple vs Nodular:

  • Simple:

    • Rapid onset: reaches maximum redness in 12 hours

    • Resolves quickly: two to three days

    • can recur in the same eye or opposite eyes.

  • Nodular:

    • gradual onset: enlarges over a couple days

    • Lasts longer

    • More discomfort then simple episcleritis.

Nodular Episcleritis

  • Symptoms: More intense than simple episcleritis.

  • Duration: Tends to last longer than simple episcleritis.

  • Association with Systemic Disease: Stronger link with systemic diseases compared to simple episcleritis.

    • Rheumatoid Arthritis (RA): 5%

    • Herpes Zoster Ophthalmicus (HZO): 7%

    • Gout: 3%

  • Appearance:

    • Focal area of hyperaemia with a raised congested nodule.

    • The nodule may be translucent

    • Nodule can be mobile.

Differentiating from Scleritis

  • Key Differences:

    • Oedema and dilated vessels in episcleritis are superficial and do not involve the sclera.

    • Scleritis patients will present with more painful symptoms.

  • Slit-lamp Examination:

    • Posterior surface appears flat in episcleritis.

    • Phenylephrine 2.5% drops cause blanching of episcleral vessels, but scleral vessels remain dilated. Eye will become white in episcleritis

  • Hue of Hyperaemia:

    • Episcleritis: Pink to red

    • Scleritis: Blue to purplish red

Management and Treatment of Episcleritis

  • Natural Course: Usually spontaneously resolves, as it is self-limiting and benign.

  • Comfort Measures:

    • Non-preserved lubricants

    • Cold compresses

    • Very short-term decongestants

  • If Discomfort is Marked: Surface steroid, e.g., FML 0.1% suspension (administered q6h). Useful for nodular episcleritis (more symptomatic).

  • Systemic NSAIDs: May help in reducing frequency and severity of recurrent episodes.

  • Medical Workup: Recommended especially for cases that are recurrent, nodular, or unresponsive to treatment. Remind patient this is a condition that may recur.