A pterygium is a soft, fleshy benign growth on the bulbar surface of the eye in the perilimbal area, which may extend onto the corneal surface. These growths can vary from nearly flat and atrophic to large, rapidly growing fibrovascular lesions that can distort the corneal topography and even reach the optical center of the cornea. Most often they are found in the nasal interpalpebral part of the bulbar conjunctiva but can occur temporally as well. They are frequently bilateral yet unequal in size. The incidence is higher in men than in women and is far more frequent in warm or tropical climates. Patients present with either just the finding of the growth or complain of irritation, redness, blurring of vision, itching, difficulty wearing contact lenses, and/or foreign body feeling. Exposure to UV light, allergens, noxious chemicals, and irritants such as wind, dirt, dust, and air pollution all contribute to the etiology of pterygiums. There may also be a genetic component as well.
ICD10CM: H11.009 – Unspecified pterygium of unspecified eye
SNOMEDCT: 77489003 – Pterygium
Differential Diagnosis & Pitfalls
Pseudopterygia (eg, or thermal burns, trauma, and marginal corneal disease)
Neoplastic lesions tend to be unilateral, gelatinous, ameboid in shape with deep irregular vascularization. Pingueculae, as noted, have a space between them and the edge of the cornea.