A pterygium is a raised, triangular or wedge-shaped growth of the conjunctiva. It is most common among those who live in tropical climates or spend a lot of time in the sun. Symptoms may include irritation, redness, and tearing.

There is a strong suggestion of a relationship between ultraviolet light exposure (UV) and the development of pterygia during the early years of life and the cumulative exposure over the next 2 to 3 decades in occupations in which there is a high component of reflected ultraviolet light.

Pterygia can affect vision if left unchecked. The corneal degradation may extend beyond the leading edge of the lesion. This means that the pterygium need not cover the visual axis to inflict significant visual compromise. Surgery must be performed before vision is affected.

The presence of pterygium and its removal, significantly influence the corneal refraction including spherical power, astigmatism, asymmetry, and irregularity, with the larger pterygium exerting the greater influence.

Surgical excisions are performed under local anesthetic with a mild sedative given afterwards.

Surgical excision of pterygia is indicated for unacceptable cosmesis and/or significant encroachment of the visual axis. The treatment of choice involves dissection and removal of the fibrous tissue down to the level of Tenon's capsule. Free conjunctival flaps are then grafted over the bare sclera from non-sun exposed conjunctiva under the upper lid. Postoperative adjuvant therapy with b-radiation, topical thiotepa, mitomycin-C and other antimetabolic agents may diminish the chance of recurrence. In cases that involve significant corneal scarring, lamellar or penetrating keratoplasty (corneal grafts) may be indicated.

Pterygia often may persist after surgical removal; these lesions appear as a fibro vascular scar arising from the excision site. These "recurrent pterygia" probably have no relationship to ultraviolet radiation, but rather may be likened to keloid development in the skin.

A follow up protocol on medium- to large-sized pterygia is recommended, at least once or twice yearly, to include a manifest refraction, corneal topography, slit lamp evaluation with measurement of the pterygium, and photo-documentation.