Updated: Jul 15, 2019
  • Author: Jerome P Fisher, MD, FACS; Chief Editor: Hampton Roy, Sr, MD  more...
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A pterygium is an elevated, superficial, external ocular mass that usually forms over the perilimbal conjunctiva and extends onto the corneal surface. Pterygia can develop on the nasal and/or temporal limbus and can affect either or both eyes. Pterygia can vary from small, atrophic quiescent lesions to large, aggressive, rapidly growing fibrovascular lesions that can distort the corneal topography, and, in advanced cases, they can obscure the optical center of the cornea. [1, 2]



The pathophysiology of pterygium is characterized by elastotic degeneration of collagen and fibrovascular proliferation, with an overlying covering of epithelium. Histopathology of the abnormal collagen in the area of elastotic degeneration shows basophilia with hematoxylin and eosin stain. This tissue also stains with elastic tissue stains, but it is not true elastic tissue, in that it is not digested by elastase. [1, 2]




United States

The incidence of pterygium within the United States varies with geographical location. Within the continental United States, prevalence rates vary from less than 2% above the 40th parallel to 5-15% in latitudes between 28-36°. A relationship is thought to exist between increased prevalence and elevated levels of ultraviolet light exposure in the lower latitudes. [3, 4]


Internationally, the relationship between decreased incidence in the upper latitudes and relatively increased incidence in lower latitudes persists.


A pterygium can cause a significant alteration in visual function in advanced cases. It can become inflamed, resulting in redness and ocular irritation.


Pterygium is reported to occur in males twice as frequently as in females.


It is uncommon for patients to present with pterygium prior to age 20 years. Patients older than 40 years have the highest prevalence of pterygia, while patients aged 20-40 years are reported to have the highest incidence of pterygium.



The visual and cosmetic prognosis following pterygium excision is good. The procedures are well tolerated by patients, and, aside from some discomfort in the first few postoperative days, most patients are able to resume full activity within 48 hours of their surgery. Those patients who develop recurrent pterygia can be retreated with repeat surgical excision and grafting, with conjunctival/limbal autografts or amniotic membrane transplants in selected patients. [5, 6]


Patient Education

Patients with pterygium should reduce exposure to ultraviolet light whenever possible. Methods of reducing ultraviolet exposure include wearing ultraviolet-blocking sunglasses, wearing a cap with a wide brim, and seeking shade from direct sunlight.

Patients who are at high risk of the development of pterygium because of a positive family history of pterygia or because of extended exposure to ultraviolet irradiation need to be educated in the use of ultraviolet-blocking glasses and other means of reducing ocular exposure to ultraviolet light.