Brief Description, Types, Sign and Symptoms, Causes And Treatment Of Pterygium

Pterygium (plural; pterygia) is a degenerative condition of the conjunctiva characterized by an elevated, wing-shaped growth of the scleral conjunctiva that encroaches upon the cornea from either side especially from the nasal side. 
A fully developed pterygium consists of three parts: Head (apical part present on the cornea), Neck (between the cornea and the sclera; limbus) and Body (sclera part extending between limbus and nasal area).

Although the exact cause of pterygium is not definitely known, the disease is more common in people living in hot climates. Therefore the most accepted view is that it is a response to prolonged effect of environmental factors such as exposure to sun ultraviolet rays), dry heat, high wind and abundance of dust. People who spend a lot of time outdoors have a higher chance of developing pterygium than others and the risk is also increased by not wearing sunglasses or hat.

Another group of Individuals that have a high incidence of developing pterygium are sports individuals such as sailors and skiers. This is because they encounter high levels of reflected UV rays. Pterygium is found to be more common in various areas where there is more ozone layer depletion and in some occupations especially those who work in dirty, dusty environments.

Pterygium should be differentiated from pseudopterygium which is a fold of bulbar conjunctiva (scleral part of the conjunctiva) attached to the cornea. It is formed due to adhesions of chemosed bulbar conjunctiva to the marginal corneal ulcer and it usually occurs following chemical burns of the eye. Pinguecula is usually considered as precursor of pterygium.

Signs and Symptoms

The individual may experience irritation which creates a feeling that something is in his eye (foreign body sensation). In addition, other symptoms include dry eyes, inflammation and redness. Large pterygium in advanced stages of development may distort the shape (curvature) of the front surface of the eye and will subsequently lead to blurred vision when it extends onto the cornea (i.e obstructing the pupil).

Treatment

Pterygium is usually managed with eye drops except when it comes with severe symptoms and affects vision that surgical intervention is recommended. Hence the treatment of pterygium depends on its size, symptoms it comes with and whether it is progressive.

If the pterygium is small and inflamed, the optometrist may prescribe lubricating eye drops in conjunction with milld steroidal or NSAIDs eye drops to relieve or reduce irritation, swelling and redness. In several cases where the pterygium is large, mature and is affecting the individual’s vision, surgical removal is considered necessary.

Unfortunately, there are chances of the pterygium regrowing again after surgical removal and according to some studies the recurrence rate is up to 40 percent. To prevent this from occurring, the eye surgeon may glue or suture a small area on the eye tissue from where the pterygium might regrow. This surgical procedure called autologous conjunctival autografting can safely and effectively reduce the risk of pterygium recurrence.

 In addition, mitomycin which slows down metabolic processes (antimetabolite) contributing to tissue growth may be topically applied.
After pterygium removal, steroid eye drops are often used for several weeks to reduce swelling and prevent regrowth.