What causes Pterygium?
The exact cause is not well understood. Pterygium occurs more often in people who spend a great deal of time outdoors, especially in sunny climates. Long-term exposure to sunlight, especially ultra-violet (UV) rays, and chronic eye irritation from dry; dusty conditions seem to play an important causal role.
When a pterygium becomes red and irritated, topical eye-drops or ointment may be used to help reduce the inflammation. If the pterygium is large enough to threaten sight, is growing or is unsightly, it can be removed surgically.