Pterygium

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Pterygium is a benign growth of the conjunctiva that extends onto the cornea, often in a wedge-shaped formation. It typically starts on the nasal side of the sclera and can extend across the cornea, potentially affecting vision if it grows large enough.

Aetiology

The exact cause of pterygium is not fully understood, but it is associated with exposure to ultraviolet (UV) light, dust, wind, and other environmental factors. Chronic irritation and inflammation of the conjunctiva are believed to contribute to its development.

Pathophysiology

Pterygium develops due to fibrovascular proliferation of the conjunctiva that grows onto the cornea. UV radiation is thought to cause DNA damage and oxidative stress, leading to inflammation and abnormal tissue growth. The presence of angiogenic factors also promotes the growth of blood vessels within the pterygium.

Risk Factors

• Chronic exposure to UV light (e.g., sunlight)
• Living in sunny or windy climates
• Outdoor occupations or activities
• Exposure to dust, wind, and other environmental irritants
• Older age
• Male gender
• Family history of pterygium

Signs and Symptoms

Common signs and symptoms of pterygium include:

• Visible, wedge-shaped growth on the conjunctiva, extending onto the cornea
• Redness and inflammation of the affected area
• Dryness and irritation of the eye
• Foreign body sensation
• Blurred vision if the growth extends over the pupil
• Astigmatism due to corneal distortion

Investigations

• Clinical history and physical examination
• Slit-lamp examination to assess the extent and characteristics of the pterygium
• Photographic documentation to monitor growth over time
• Visual acuity testing to evaluate any impact on vision
• Corneal topography to assess astigmatism and corneal shape

Management

Primary Care Management

• Education on UV protection: Advising patients to wear sunglasses and hats to reduce UV exposure
• Lubricating eye drops: To alleviate dryness and irritation
• Topical anti-inflammatory medications: Such as corticosteroids or nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation
• Referral to an ophthalmologist: For evaluation and consideration of surgical removal if the pterygium is large, growing, or causing visual impairment

Specialist Management

• Surgical excision: Removal of the pterygium is indicated if it is causing significant symptoms, vision impairment, or cosmetic concerns. Techniques include bare sclera excision, conjunctival autograft, and amniotic membrane transplantation.
• Adjunctive therapies: Use of mitomycin C or other agents to reduce the risk of recurrence post-surgery
• Regular follow-up: To monitor for recurrence and manage any complications

References

1. NICE. (2024). Pterygium: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Pterygium. Retrieved from NHS
3. British Medical Journal (BMJ). (2022). Pterygium: Diagnosis and Management. Retrieved from BMJ
4. American Academy of Ophthalmology (AAO). (2021). Clinical Practice Guidelines: Pterygium. Retrieved from AAO

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