A pterygium is a wing-shaped growth of tissue that extends from the white of your eye onto the clear front surface (the cornea). Sometimes called surfer’s eye, it develops when cells at the border between the conjunctiva and cornea begin to proliferate abnormally, sending a wedge of fleshy, vascular tissue creeping toward the center of your vision. Pterygia are benign, not cancerous, but they can grow large enough to distort your cornea and blur your sight.
What Happens Inside the Eye
Your eye has a thin, clear membrane called the conjunctiva that covers the white part (sclera) and a boundary zone called the limbus where the conjunctiva meets the cornea. Stem cells at this boundary normally act as a barrier, keeping conjunctival tissue from migrating onto the cornea. In a pterygium, those limbal stem cells become altered, and the barrier breaks down. Conjunctival tissue, blood vessels, and inflammatory cells then advance across the cornea in a process called conjunctivalization.
Under a microscope, a pterygium shows several layers of disruption: abnormally proliferating surface cells, an overgrowth of mucus-producing goblet cells, a damaged protective layer beneath the surface (Bowman’s layer), and a buildup of collagen and elastin fibers deeper in the tissue. This is why a pterygium looks fleshy and reddish. It’s an active, living growth with its own blood supply, not just a surface blemish.
How It Differs From a Pinguecula
A pinguecula is a small, raised, yellowish or white bump that stays on the conjunctiva and never crosses onto the cornea. It contains deposits of protein, fat, or calcium and generally doesn’t affect vision, though it can cause mild dryness or irritation. A pterygium, by contrast, is a wedge-shaped growth that extends onto the cornea. Both can appear on either side of the eye, and both are linked to UV exposure, but a pterygium carries the added risk of corneal distortion and vision loss. Think of a pinguecula as a spot that stays put and a pterygium as one that keeps advancing.
Causes and Risk Factors
Long-term ultraviolet radiation is the dominant cause. The World Health Organization estimates that solar radiation accounts for 42% to 74% of pterygium cases worldwide. People living in tropical and subtropical regions, sometimes called the “pterygium belt,” are hit hardest. A systematic review found that populations in areas with high or very high annual UV levels had a crude pterygium prevalence of roughly 19%, compared with about 5% in moderate-UV regions, a three- to four-fold difference.
Outdoor work is one of the strongest individual risk factors, alongside older age and male sex. Wind, dust, and dry environments also contribute by chronically irritating the eye’s surface. Genetic susceptibility plays a role too; not everyone with the same sun exposure develops a pterygium, suggesting some people’s limbal stem cells are more vulnerable to UV-induced damage than others.
Symptoms and How It Progresses
Many small pterygia cause no symptoms at all. As the growth becomes more prominent, the most common complaints are a persistent feeling of something in the eye, redness, and irritation. Dryness is common because the raised tissue disrupts the smooth tear film across the eye’s surface.
Clinicians grade pterygia partly by how thick and opaque they are. A thin, translucent pterygium (grade 1) may have little measurable effect on vision. A thick, fleshy one (grade 3) that completely obscures the blood vessels beneath it is associated with significantly worse optical quality. As the growth creeps closer to the center of the cornea, it can pull on the corneal surface and create irregular astigmatism, a type of distortion that glasses alone may not fully correct. In advanced cases, the pterygium can scar the cornea, and that scarring may persist even after surgical removal.
Managing Symptoms Without Surgery
If a pterygium is small, stable, and not affecting your vision, surgery isn’t necessary. Lubricating eye drops (artificial tears) relieve the dryness and gritty sensation that come from an uneven tear film. When a pterygium becomes inflamed and noticeably red, a short course of anti-inflammatory steroid drops can calm it down. These measures don’t shrink the growth, but they keep you comfortable and are often all that’s needed for years, sometimes indefinitely.
When Surgery Is Recommended
Surgery enters the conversation when a pterygium threatens your vision, continues to grow toward the center of the cornea, or causes persistent discomfort that drops can’t manage. The procedure is done on an outpatient basis under local anesthesia and typically takes under 30 minutes.
The simplest approach, bare sclera excision, removes the pterygium and leaves the underlying white of the eye exposed to heal on its own. This method has largely fallen out of favor because the recurrence rate is high, with studies linking it to six times greater odds of the pterygium growing back compared to more advanced techniques.
The current preferred method is pterygium excision with a conjunctival autograft. After removing the growth, the surgeon takes a thin patch of healthy conjunctival tissue from under your upper eyelid and secures it over the bare area. The graft includes limbal stem cells, which helps rebuild the natural barrier that prevents regrowth. Recurrence rates with this technique drop to as low as 5%, and some studies report even lower figures. The graft can be attached with tiny sutures or with tissue glue. Fibrin glue tends to mean less operative time and less postoperative discomfort.
After surgery, expect to use antibiotic and anti-inflammatory drops for several weeks. The eye will be red and irritated for the first week or two, with full healing typically taking a month or more. Most people return to normal activities within a few days, though the eye may look cosmetically red for several weeks.
What Happens if You Leave It Alone
A pterygium that stays small and stable may never need treatment beyond artificial tears. But one that continues growing can pull on the cornea hard enough to cause permanent astigmatism, scar the corneal surface, and in rare cases restrict eye movement. Corneal scarring is the most concerning long-term risk because it can affect your vision even after the pterygium is surgically removed. The longer a growing pterygium sits on the cornea, the greater the chance of irreversible changes, which is why monitoring matters even if you’re not ready for surgery.
Protecting Your Eyes
Since UV radiation drives the majority of cases, the single most effective preventive step is wearing sunglasses that block 100% of both UVA and UVB rays whenever you’re outdoors. Wraparound frames offer the best protection because they limit light entering from the sides, where pterygia typically start growing. A wide-brimmed hat reduces UV reaching your eyes by roughly half on its own and pairs well with sunglasses. If you work outdoors, consistent use of both is especially important. Keeping your eyes lubricated with artificial tears in windy or dusty conditions also reduces chronic surface irritation, one of the contributing factors to pterygium formation.