Wednesday, April 23, 2014

Pterygium and Pinguecula

Definition

A pterygium is a fleshy growth that invades the cornea (the clear front window of the eye). It is an abnormal process in which the conjunctiva (a membrane that covers the white of the eye) grows into the cornea.

A pinguecula is a yellowish patch or bump on the white of the eye, most often on the side closest to the nose. It is not a tumor but an alteration of normal tissue resulting in a deposit of protein and fat. Unlike a pterygium, a pinguecula does not actually grow onto the cornea. A pinguecula may also be a response to chronic eye irritation or sunlight.

Description

Although pterygium and pinguecula sound like mysterious, arcane diseases, they are actually quite common, usually benign eye conditions. These lesions appear as a whitish-yellowish bump or fleshy "growth" on the exposed conjunctiva.

If the bump appears only on the white part of the eye, it is called a pinguecula. If it appears to "grow" onto the cornea, forming a winglike structure, it is called a pterygium from the Greek word for wing (pterygion).

Because these lesions look like growths, people sometimes worry that they may become malignant. In actuality, the underlying process is a degenerative one and usually does not lead to anything catastrophic such as a serious loss of vision or blindness. Most pingueculae and pterygia are slow growing and rarely cause significant problems.

Causes

Although the causes of these lesions are not completely understood, prolonged exposure to ultraviolet and infrared radiation from sunlight has been implicated. Other environmental irritants, such as dust and wind, may play a role as well. People who spend considerable time in the sun are much more likely to have pingueculae or pterygia than indoor folks. Susceptible groups include individuals who work outdoors such as farmers and fishermen or those who engage in outdoor activities such as golfing and gardening.

Symptoms

Usually a bump appears on the eye surface without any other symptoms. Individuals may worry that a foreign body is trapped in the eye or perhaps that a cancer is growing. An examination by an ophthalmologist will allay these worries.

Treatment

A conservative approach is recommended for most people. Artificial tears may provide comfort, relieving the sensation of a foreign body. Occasionally, a lesion becomes mildly inflamed; in this case, a mild optical decongestant or, rarely, an anti-inflammatory agent may be prescribed.

Surgery is the only way to remove a pinguecula or pterygium, but the results can be disappointing. Even with modern techniques, the recurrence rate is often as high as 50 to 60 percent. Surgery is not recommended unless a pinguecula or pterygium is causing significant problems.

Three types of problems may warrant surgery.

First, vision may be affected by a pterygium large enough to involve the cornea's center visual zone or that causes astigmatism. Surgery may be able to improve the clarity of the optical center and limit excessive or irregular astigmatism.

Second, a pterygium (rarely a pinguecula) may be unsightly and cosmetically objectionable. Surgery can reduce the size of a fleshy pterygium, but complete elimination is often not possible.

Third, either a pinguecula or pterygium may cause excessive discomfort due to dryness or a chronic foreign body sensation. Surgery usually improves comfort, but sometimes irritating symptoms may remain.

Surgery can be performed as an outpatient procedure with local anesthesia; and pain is uncommon.

Healing typically takes many weeks with patients applying prescribed topical eyedrops or ointments several times a day. In the early phase of healing, the eye may be slightly swollen and bloodshot in appearance. Eventually the surgical site improves in comfort and appearance.

Questions

Is the diagnosis pterygium or pinguecula?

How serious is this?

Do you recommend the use of a decongestant or anti-inflammatory medication?

Would surgery help?

How successful is surgical removal?

Prevention

There is no known method of preventing a pinguecula or pterygium. However, a prudent precaution is to protect the eye from undue sun exposure by wearing protective eyewear with good ultraviolet blockage, or at least a rimmed hat. Fortunately, most cases of pinguecula or pterygium do not constitute worrisome eye disease, and surgery usually is not necessary.