What is a pterygium?

A pterygium is a raised, triangular or wedge-shaped growth of conjunctival tissue which grows over the surface of the cornea (the transparent dome at the front of the eye). It usually occurs on the nasal side of the cornea. In the early stages only small grey opacities at the junction of the cornea and the white of the eye can be seen. The conjunctiva can then overgrow these opacities and encroach on to the cornea in a triangular fashion.




What causes a pterygium?

Pterygia typically develop in individuals who have been living in hot, dry climates and may be a response to:

• Long-term exposure to sunlight, especially ultraviolet rays
• Chronic irritation from the dry climate

There is often a family history so genetic factors, perhaps due to the shape of the front of the eye may play a role.


What are the symptoms?

• Irritation
• Redness
• Tearing
• Astigmatism
• Reduced vision

Vision is only affected in a minority of cases when the pterygium is very extensive and grows towards the centre of the cornea, although they may induce changes in astigmatism at an earlier stage.


How can pterygia be treated?

Treatment depends on symptoms. If the pterygium is small it can be safely left, especially in individuals residing in temperate climates. Eye-drops or ointments can be prescribed to relieve redness and irritation.

If troublesome pterygia can be excised. Surgery is painless and performed either under local or general anaesthesia as a day case and without the need for over-night hospital stay. The surgery takes approximately half an hour. Indications for removal include:

• Chronic eye irritation
• Disturbance of vision
• Cosmetic.

The surgery involves removal of the conjunctival tissue over the cornea. In order to try and prevent re-growth, this is often combined with the grafting of a free flap of adjacent conjunctiva over the bare area of the white of the eye (the sclera). Some surgeons also advocate the use of other topical therapies such as Mitomycin-C (a chemical used in cancer treatment) and radiation to reduce recurrence.

If there has been extensive growth towards the centre of the cornea a laser procedure may be required to smooth out surface irregularities and improve vision. The laser used is called an Excimer laser and is the same as that used to treat long- and short-sight.


What happens following surgery?

Typically the eye feels sore following surgery for a few days. Eye drops in the form of antibiotic/steroid combinations are administered for a few weeks. Redness of the eye usually settles after a few months. Recurrence (re-growth) can occur weeks/months after the surgery and occurs is about 5-10% of eyes. Patients can usually resume normal activities a week after surgery.