What is "pterygium"

Pterygium \Pte*ryg"i*um\, n.; pl. E. Pterygiums, L. Pterygia. [NL., fr. Gr. ?, properly a dim, akin to ? a feather.] (Med.) A superficial growth of vascular tissue radiating in a fanlike manner from the cornea over the surface of the eye.

n. (context medicine English) An abnormal mass of tissue in the corner of the eye that obstructs vision

1. n. a thickened triangular layer of conjunctiva extending from the nasal edge of the eye to the cornea; pterygia arise from irritation of the pinguecula

2. [also: pterygia (pl)]

Pterygium, also known as surfer's eye, most often refers to a benign growth of the conjunctiva. A pterygium commonly grows from the nasal side of the conjunctiva. It is usually present in the palpebral fissure. It is associated with and thought to be caused by ultraviolet-light exposure (e.g., sunlight), low humidity, and dust. The predominance of pterygis on the nasal side is possibly a result of the sun's rays passing laterally through the cornea, where it undergoes refraction and becomes focused on the limbic area. Sunlight passes unobstructed from the lateral side of the eye, focusing on the medial limbus after passing through the cornea. On the contralateral (medial) side, however, the shadow of the nose medially reduces the intensity of sunlight focused on the lateral/ temporal limbus.

Pterygium refers to any winglike triangular membrane occurring in the neck, eyes, knees, elbows, ankles or digits.

In the eye, a pinguecula is called a pterygium if it invades the cornea.

The term comes from the Greek word pterygion meaning "wing".