Pterygium (Greek, pterygion, meaning wing-like) is a benign proliferation of fibrovascular tissue. It usually originates in the nasal conjunctiva on the horizontal meridian of the limbus. It progressively encroaches onto the cornea and visual axis. Its appearance ranges from flat and white to thick, pink or red, and fibrovascular. Typically, it assumes a triangular appearance, with the apex directed toward the pupil. Predisposing factors include exposure to ultraviolet light, wind, and dust. Older individuals living in warmer areas with high levels of sunlight are more likely to develop pterygia.
Pterygia may be asymptomatic or become inflamed, causing mild symptoms of irritation and foreign-body sensation. Decreased visual acuity may result as the pterygium encroaches on the visual axis or if the lesion induces astigmatism.
Pinguecula (Latin, pingueculus, meaning fatty) is a common degenerative lesion of the bulbar conjunctiva, also arising in the horizontal meridian. It appears as a light brown or yellow-white amorphous, slightly raised conjunctival tissue adjacent to the limbus. It too may be asymptomatic or become episodically inflamed; however, it may enlarge and become a pterygium.
Management and Disposition
Mild disease can be treated with artificial tears or a topical vasoconstrictor (pheniramine/naphazoline ophthalmic). In more severe cases, consultation with an ophthalmologist is appropriate regarding topical steroids and topical nonsteroidal anti-inflammatory drugs (NSAIDs). Surgical excision by the ophthalmologist is indicated if the pterygium interferes with contact lens wear, encroaches significantly on the visual axis resulting in induced astigmatism or opacity, or restricts eye movement.
Pinguecula. A small area of yellowish “heaped up” conjunctival tissue is seen adjacent to the nasal limbus. (Photo contributor: Department of Ophthalmology, Naval Medical Center, Portsmouth, VA.)
Pterygia are more likely than pinguecula to be found on the nasal conjunctiva and bilateral.
Pterygia and pingueculae are found on the horizontal meridian. Conjunctival neoplasms often occur in axes other than the horizontal axis.
Following surgical excision, recurrence of pterygia is common.
Pterygium mimics include localized conjunctival neoplasia, conjunctivitis, and episcleritis.
Pterygium. Pterygium appears as a raised vascular triangular area of bulbar conjunctiva that encroaches onto the cornea. (Photo contributors: Top: Rebecca Kasl, MD; Bottom: Andrew J. Hendershot, MD.)