contacts-logo Pterygium

A Pterygium Must be Treated Timely and Properly to Avoid Permanent Vision Loss

What is a Pterygium?

A pterygium (pronounced “ter-ridge-e-um”) is a growth of fibrovascular tissue that extends from the “white” part of the eye onto the cornea (clear window covering the iris).  A pterygium is a raise, whitish-yellowish colored triangular-shaped wedge of fibrovascular tissue.  The base of the triangle of the pterygium is located on the visible part of the conjunctiva (conjunctiva is the clear outer tissue covering the white part of the eye) and the apex of the pterygium is on the cornea.  Approximately 90% of pterygium occur on the nasal side of the eye.

A pterygium is a degeneration of the conjunctiva (stromal layer).  The normal tissue gets replaced by thick, twisted elastic fibers.

Signs and Symptoms of a Pterygium

Pterygia are often not readily apparent to the individual in their early stagePterygium photograph MasterEyeAssoc resized 600 and may be discovered by an eye doctor during a routine eye exam.  In more advanced cases they are completely visible to the patient.  Often the irregular surface of the eye caused by the elevation of the pterygium interferes with the proper distribution of tears over the eye’s surface resulting in irritation, discomfort and dryness.  Sometimes a pterygium can cause warpage of the cornea curvature resulting in blurred vision from induced astigmatism.

Causes of Pterygia

The primary cause of a pterygium is ultraviolet light.  Both UV-A and especially UV-B cause the development of pterygia.  Other factors contributing to the development of pterygia are wind, dirt, dust, air pollution, allergens and noxious chemicals.  Heredity is also a potential factor in the development of pterygia.

Degenerated tissue within the leading growing edge (the apex) of the pterygium invade and break-up cells of the cornea (Bowman’s membrane and superficial stroma).  T-lymphocytes found in the pterygium epithelium suggest some role of cell immune response in pterygium formation.

Pterygium are discovered much more frequently in areas of warm, dry climates with great sun exposure.  Pterygium occur more frequently (3 times more often) in people of African descent than in whites;  and men are affected slightly more than women.

Treatment for Pterygium

All patients with a pterygium should avoid environments of high amounts of wind, dust, pollen, chemicals, etc.  All should also wear UV blocking spectacles and sunglasses and freely use unpreserved artificial tears.  See below for additional recommendations.

Treatment for Mild Pterygium  

Inflamed or irritated pterygia can be treated with corticosteroid eye drops such as Lotemax during periods of inflammation.

Treatment for Advanced Pterygium

Tumors (Conjunctival intraepithelial neoplasia) must be ruled out by biopsy if suspected.

A pterygium can cause significant vision loss if left untreated and if the lesion extends into the visual axis (in front of the pupil area).  It is worth noting that the degeneration and negative effects of a pterygium extend about 3 millimeters past the visible leading edge of the growth.  Therefore, it is important to treat the pterygium well before it gets near the pupillary area. 

Surgery by excision is recommended for improved cosmetic appearance, induced astigmatism or when growth of the pterygium nears the central cornea.