Degenerations and Dystrophies: Conjunctiva

Dystrophies: conditions that are inherited

Degenerations: something that occurs due to some type of noxious influence (e.g., aging, nutrient intake, inflammation).

Dystrophies and Degenerations of the Conjunctiva

Pingueculae

  • Definition: Degeneration of the conjunctiva.

  • Appearance: Yellowish gelatinous nodule on the bulbar conjunctiva near the nasal and temporal limbus.

  • Pathology: Hyaline degeneration with elastic fibers being laid down.

  • Causes: Associated with chronic UV exposure and chronic irritation from wind and dust.

  • Prevalence: Ubiquitous in Australia, benign, usually asymptomatic, and of little significance (no threat to sight).

  • management: reassurance, advice on UV protection, tear supplements can be used to reduce dryness/ irritation. Surgery is rarely required.

Pterygium

  • Definition: Wing-shaped vascularized growth extending onto the cornea.

  • Risk Factors:

    • More common in hot climates.

    • Chronic UV exposure, ocular dryness, and irritation.

  • Common Locations: Most commonly nasal; rare temporal pterygium.

  • Associated Signs: Stocker’s line - iron line in corneal epithelium forward of the apex.

  • Symptoms:

    • Ocular surface irritation.

    • Dryness and foreign body sensation.

    • Potential for pterygium to cause dellen (localized corneal depression due to chronic disruption of tear film).

  • Impact on Vision: Can affect vision by increasing astigmatism (worse with the trend towards regular astigmatism) and irregular corneal distortion.

    Stocker's Line

Topography Pterygium

  • corneal topography can be a useful tool

  • establishes a baseline for pterygium size and effects on corneal shape and astigmatism (WTR increase)

  • allows precise monitoring for future follow-up

  • useful for illustrating to patients the effects of the pterygium

Management of Pterygium

  • Prevention and Advice:

    • Advise on UV protection.

    • Use of eye lubricants for irritation symptoms.

  • Acute Management: Redness/inflammation can be treated with anti-inflammatory drops (e.g., FML).

  • Indications for Surgical Removal:

    • Visual acuity concerns.

    • Irregular astigmatism (distorted keratometer mires).

    • Cosmetic reasons.

    • Persistent inflammation/redness.

    • Pterygium size - if it extends more than halfway between the pupil margin and the centre of the cornea, consider referral.

Surgical Treatment of Pterygium

  • Procedure: Surgical removal of pterygium; bare sclera covered with an autoconjunctival graft.

  • Benefits: Reduces recurrence rates (0.5-5%, depending on specific surgical technique).

  • Additional Therapy: Mitomycin C used post-op can aid in reducing recurrence.

  • Post-Surgery Care:

    • Discomfort, photophobia, and blurred vision expected for the first week.

    • Application of antibiotic (Chloramphenicol) and steroid (Predforte) eye drops every 4 hours during the first month.

    • Gradual return of corneal curvature to normal in the months following surgery.

Pterygium and Ocular Surface Complications

  • Research Findings: Higher rates of ocular surface squamous neoplasia found in pterygium specimens (13.3%) than expected based on clinical exam.

  • Caution: Temporal pterygium may indicate squamous dysplasia or squamous cell carcinoma.

Squamous cell carcinoma

Concretions (Lithiasis)

  • Definition: Small punctate, hard yellow deposits in the conjunctiva. Made up of degenerating epithelial cells and proteins that become trapped in the conjunctiva and then undergo calcification over time.

  • Common Location: Typically found in the inferior palpebral conjunctiva.

  • Prevalence: Very common in elderly patients, generally asymptomatic as they usually sit under the epithelium.

  • Symptoms: typically, asymptomatic. Can lead to irritation or foreign body sensation if large concretion erodes through the epithelium.

  • Management for Irritation:

    • Removal using a bent 25-gauge needle at the slit lamp with local anaesthetic.

    • Followed by prophylactic coverage with broad-spectrum topical antibiotic (e.g., Tobradex or Chloramphenicol).

Conjunctivochalasis

  • Definition: A normal aging change to conjunctiva characterized by folds of redundant conjunctiva.

  • Common Presentation: Between the globe and lower eyelid, protruding over the lid margin.

  • Symptoms: Often asymptomatic but can exacerbate dry eye symptoms and commonly contributes to epiphora.

  • Management:

    • Topical lubricants for symptomatic relief.

    • Treatment for any accompanying blepharitis.

    • Short course of topical steroids may be helpful if symptomatic.

    • Severe cases may require surgical resolution (conjunctival resection).

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