Pterygium –  Definition, Causes, Treatment, and Prevention.

Definition

Pterygium means “wing” and refers to a wing-like growth on the surface of the eye.  It (growth) spreads from the conjunctiva over the cornea. The conjunctiva is the mucous membrane covering the whites of the eyes (sclera) and the cornea is the clear windshield of the eye.  Pterygia are more common in areas of the world nearest the equator.

Pterygium is more common in countries near the equator, therefore long-term exposure to sunlight, particularly ultraviolet (UV) rays have been a suggested cause. In addition, others believe that chronic eye irritation may play an important role. Therefore, it occurs more often in people who spend time outdoors, particularly in sunny climates.

Pterygiums are benign (not malignant) tumors. Hence it doesn’t invade the eye, sinuses or brain. It does not spread to other parts of the body (metastasize).

Epidemiology of Pterygium

The prevalence of pterygium was found to be 10.2% in the world, with the highest prevalence in low altitude regions. Increased incidence of it is noted in the tropics and in an equatorial zone between 30° north and south latitudes. Higher incidence is associated with chronic sun exposure (ultraviolet light), older age, male sex, and outdoor activity.

Types of Pterygium

A pterygium has two types of progressive or atrophic.
The differences between the progressive and atrophic pterygium

	Progressive pterygium	Atrophic pterygium
Appearance	Thick and fleshy	Thin and membranous
Blood vessels	Very prominent	Very few blood vessels giving a pale appearance
Cap in front of the head	Present	Absent
Progression	Continues to advance further into the cornea	Static after an initial period of growth

Risk factors

• Ultraviolet exposure (single most significant risk factor)
• Exposure to irritants (dust, sand, wind)
• Inflammation
• Dry ocular surface

Causes of Pterygium

• The main cause is almost certainly lifetime sun exposure – UV light. People who live in hot, dry, sunny regions and spend a lot of time outdoors have a higher chance of developing a pterygium than others. The risk is also increased by not wearing sunglasses or a sun hat.
• Sports people such as sailors, surfers, and skiers also have a high incidence because of the high levels of reflected UV light they encounter. Pterygia are also more common in areas where there is ozone layer depletion, such as New Zealand.
• It usually occur in people aged 20 to 50, and are more common in men, probably due to an increased likelihood of an outdoor work environment.

Symptoms

Symptoms of pterygium may include:

• Redness and inflammation, particularly if the pterygium is growing
• Blurred or distorted vision, if it grows onto the cornea
• Burning
• Gritty feeling
• Itching
• The sensation of a foreign body in the eye
• Sometimes a pterygium does not cause any symptoms other than its appearance.

Eye with pterygium

Complications of Pterygium

Complications depend mainly on the size of pterygium and the severity of corneal invasion:

• Corneal astigmatism with blurred vision.
• Dry eyes.
• Recurrent eye irritation.
• Red eyes and inflammation.
• Difficulties in wearing contact lenses.
• Ocular motility restriction.
• Cosmetically disturbance.

Diagnosis and test

Your healthcare provider will ask about your health history and give you a physical exam. This may include a detailed eye exam, especially if you have eyesight symptoms. Your healthcare provider may refer you to an eye doctor (ophthalmologist).

Your eye doctor will look closely at the growth to make sure it is not another eye condition. In some cases, the doctor may take a small sample (biopsy) of it. The sample is checked for cancer. Most people will not need a biopsy.

Treatment and medications

Pterygium usually doesn’t require treatment if symptoms are mild. If a temporary worsening of the inflamed condition causes redness or irritation, it can be treated with:

• Lubricating eyedrops or ointments, such as Blink or Refresh drops
• Occasional use of vasoconstrictor eyedrops, such as Naphcon A
• A short course of steroid eyedrops, such as FML or Lotemax

Surgery- Grafting with fibrin glue

The surgery consists of removing the pterygium and replacing it with a graft of tissue, which is glued into place. There are no sutures and the procedure is completely painless. Because of the medications you’ve received, you won’t be able to drive yourself home.

The use of fibrin glue in pterygium surgery with conjunctival autographing significantly reduces surgery time, improves postoperative patient comfort and results in lower recurrence rate compared with suturing.

Prevention of Pterygium

• You may help prevent it by wearing sunglasses every day, even on cloudy days. Choose sunglasses that block 99%-100% of both ultraviolet A (UVA) and ultraviolet B (UVB) radiation.
• Wraparound sunglasses provide the best protection against ultraviolet light, dust, and wind.
• Experts also recommend wearing a hat with a brim to protect the eyes from ultraviolet light.
• To keep your eyes moist in dry conditions, apply artificial tears.