Flip over a bottle of sunscreen, and there’s a good chance you’ll find a warning embedded in the fine print: “Avoid contact with eyes.”
Let’s be clear. Unless you’re eager for a world of hurt, under no circumstances should you be rubbing sunscreen directly onto your eyeballs. But in an effort to avoid the sting, many might be overlooking important, sun-sensitive areas of the face—and it could come at a serious cost to health.
Despite making up less than one percent of the body’s skin, the covering on our eyelids is where up to 10 percent of basal cell carcinomas, the most common form of skin cancer, occur. Now, two recent studies reveal that these delicate regions are also where people most often skimp when applying sunscreen and moisturizers containing sun-protection factor (SPF).
To make matters worse, many might be unaware that they’ve left these vulnerable areas unprotected. In one study, most subjects walked away confident that they’d done a good job covering the entire face with the product; in the other, a second attempt at application yielded only a slight improvement over the first, even though the participants had been educated about the importance of treating their eyelids.
“These are very astute and potentially important medical findings,” says David Fisher, a cancer biologist and oncologist at Massachusetts General Hospital and the Dana Farber/Harvard Cancer Center who was not involved in the study. “I can’t tell you how much skin cancer we diagnose in our department in exactly that little area.”
Both studies were led by ophthalmologist Austin McCormick and University of Liverpool vision scientist Kevin Hamill. In the first, British volunteers were instructed to apply sunscreen to their faces. The researchers then imaged their freshly-lotioned mugs with a UV-sensitive camera that picked up bright, reflective spots where the cream was absent.
An ensuing computer analysis revealed that the participants left about 10 percent of their faces sunscreen-free—and when the researchers homed in on the region around the eyelids, the amount of untreated skin rose to 14 percent. McCormick was especially troubled to see that the most problematic area of all was a small spot where the upper and lower eyelids met, closest to the nose, which 44 out of 57 participants failed to cover. The eyelids already have the thinnest skin on the body, making this region especially sensitive to the penetrating powers of sunlight. But cancer at these inner corners can be particularly challenging to deal with, McCormick explains, because it’s easy for malignant cells to invade the tissues directly underneath.
Even after being warned about the risks of leaving their faces exposed to sun, the study subjects were only able to up their coverage by a meager amount in a second trial, with eight percent of their faces remaining unprotected. In a questionnaire, several participants admitted that they’d intentionally avoided their eyelids out of concern that the cream would sting their eyes.
These concerns aren’t shocking, says Maria Wei, a dermatologist and melanoma specialist at the University of California, San Francisco who was not involved in the research. Apart from wanting to avoid directly jamming cream into the eyes, people tend to “give this spot a wide berth...so when they sweat, it won’t run into the eyes,” she says.
It was a discouraging result, but McCormick also sympathizes, saying “it can be hours of a red, watery eye once [sunscreen] seeps in.” Even if the potential irritation is temporary, it makes for a big deterrent, he says.
The researchers then repeated their experiments, this time including a moisturizer marketed to contain SPF, an increasingly common staple on pharmacy shelves. “We thought maybe moisturizer would be applied more thoroughly because people would think that it wouldn’t sting the eyes in the way a sunscreen might,” McCormick says of the second study, published today in the journal PLOS ONE.
But exactly the opposite was true. Armed with sunscreen, participants missed about 11 percent of their faces—but when smearing on moisturizer, the uncovered proportion jumped to almost 17 percent. Once again, most subjects neglected the inner corners of the eyes.
A follow-up questionnaire showed the vast majority of the participants felt certain they’d done an adequate job applying the creams to all areas of the face. This could be a dangerous mindset, Fisher says. People who unknowingly misapply sunscreen might be lulled into a false sense of security, and be tempted to spend more time outdoors, he says. Repeated enough times, this process might put some of the most sensitive—and most exposed—areas of the body at risk.
Before letting their study subjects go, however, the researchers showed them the photos they’d taken, pointing out the regions of their faces left unprotected. Most responded by resolving to be more conscious of coverage in the future.
“This really shows what a terrible paradox we’re in,” Fisher says. “[Skin cancer] has the distinction of being exceptionally common, but we also know more about its cause than [any other cancer], and how we can block it. We should be doing better.”
But the results of the first study suggest that education and public health campaigns might not be enough to, well, save face. “We expected that showing someone the areas they missed would help them,” McCormick says. “But that intervention wasn’t as effective as we’d thought.” McCormick also notes that, because these measures were taken from the subjects of an academic study, people might have been on their best behavior; sunscreen application practices in the general population could actually be worse.
Even among the most steadfast of sunscreen users, application habits are all over the map, says Nisma Mujahid, a Boston University researcher and medical student who specializes in the biology of skin cancers, but was not involved in the study. People typically apply less than half of the recommended amount of sunscreen and end up putting on much less SPF than they think, she says.
At the end of the day, sunscreen simply doesn’t begin to cover it.
To achieve full protection from UV rays, then, people can’t rely on sunscreen alone. Henry Lim, a dermatologist with Detroit’s Henry Ford Health System who was not involved in the study, recommends the “total package.” That includes keeping to shady spots when outdoors and donning clothing to cover most of the body (bonus points if the material is imbued with UV protection).
Any exposed skin left over should be slathered with the prescribed dose of broad-spectrum sunscreen at SPF30 or above, Lim says. Sunscreens are typically safe for the eyelid region, but for those with sensitive skin, zinc oxide and titanium dioxide formulations are often gentler. There are even now some creams specifically marketed for eye-adjacent regions. But to fully shield that ultra-sensitive face, Lim says, all this should be topped off with a wide-brimmed hat and UV-blocking sunglasses.
This might seem like a lot of work, but armoring up is the safest bet. “We need to convey a message to patients that they can implement,” Lim says.
Of course, none of this is intended to demonize sun exposure, Mujahid says. Soaking up sunlight is a natural part of human existence, and it’s well established that it boosts vitamin D levels and mental wellbeing. The right amount will of course vary from person to person, and ultimately, it’s important to strike a balance.
But the risks of UV damage are too serious to brush off, Mujahid says. “You can treat vitamin D deficiency, but you can never reverse exposure to the sun’s harmful rays.”