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.

  

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.

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).