What is a pterygium?
Pterygium is a growth which arises on the conjunctiva and grows towards and infiltrates, the surface of the cornea. As it grows, it typically forms a triangle with the head of the pterygium towards the center, and the body and tail (the base of the triangle) towards the canthus (the point where the upper and lower eyelids meet). The elevated growth typically develops over the edge of the cornea and grows inward where it eventually may cause impaired vision.
What causes a pterygium? Risk factors for development of pterygium
The origin of pterygia is not completely clear and doctors are still researching the exact cause of a pterygium. Studies show high exposure to ultraviolet light and dry conditions increase the probability of the growth. Pterygia are more common for patients in warm climate areas. Trauma from exposure to pollen, dust, sand, wind, smoke and other environmental stimuli can also add to the risk of pterygium formation. If sunglasses are not worn in the regions of sunny climates, this increases the risk of developing pterygia. People with light color eyes and light skin pigmentation may also have a higher risk, too.
Symptoms of pterygium
The symptoms of pterygium are often not severe, but may include eye irritation, redness, and blurred vision. Most patients complain of itchiness, scratchiness and burning. A pterygium grows slowly, and may not affect your vision unless it grows directly over the center of the cornea. A pterygium can also cause contact lens intolerance.
Surgical treatment for Pterygium is not necessary unless the pterygium is irritating despite the use of artificial tears, is causing astigmatism or visual loss, or is approaching the line of vision. In many instances, patients prefer to have the pterygium removed for cosmetic purposes. You should be aware that pterygia can grow back after surgery rapidly and sometimes, violently. Patients also experience dryness and irritation after the removal, but surface lubrication and other medications can be used as treatment and to help prevent recurrence.
Many alternatives have been suggested for the surgical treatment of pterygiums. During bare sclera excision, an area of the white part of the eye is left uncovered as a barrier for growth into the cornea. In primary closure, the pterygium is removed and the conjunctiva closed. Conjunctival autografting or the removal and transplantation of healthy conjunctiva not exposed to the sun from a different part of the eye, results in a lower rate of recurrence than primary closure. However, sutures are used to secure the tissue to its new location. This increases the amount of postoperative discomfort and may increase the amount of inflammation. Alternatively, amniotic membrane grafts can be used. During this technique, instead of harvesting the conjunctiva, a piece of donor amniotic membrane is glued in place using Tisseel Duo Quick (Baxter). The use of glue instead of sutures leads to less postoperative pain, faster recovery and shortened surgical time. The rate of recurrences are similar between conjunctival autografts and amniotic membrane grafts which are a lot lower than primary closure. Some research studies have suggested higher rates of recurrence with autografts and others with amniotic membrane grafts.