Next time you're out in the sun, don't forget to slip, slop and slap your eyelids.
UK research has found they're the most commonly neglected part of the face when people apply sunscreen - and even more so when using sun protection factor (SPF) moisturisers.
"When applying both sunscreen and moisturiser, the area around to eyes is often missed, particularly near the nose," the University of Liverpool study's authors wrote in journal PLOS One.
Eighty-four participants - three-quarters of them female - applied SPF30 sunscreen or moisturiser, then were exposed to UV radiation and photographed with a UV-sensitive camera.
Around 11 percent of the face on average is missed when using sunscreen, and 16.6 percent with moisturiser, the study found. Most of the time the area missed was the eyelids - 14 percent miss them completely when using sunscreen, and 20.9 percent with moisturiser.
"Participants covered a smaller area of the face when using moisturiser compared to sunscreen."
And most of them were completely unaware they'd failed to cover up properly.
"The addition of SPF to daily moisturisers has lots of potential advantages in terms of likely increase in general protection in all weather conditions," the study said.
"However, our data show that those potential advantages may be offset by incomplete coverage to areas at high risk of skin cancer and a mistaken belief that the face is fully protected. In many environments, the risk that you are unaware of poses the greatest danger."
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The researchers said it wasn't clear why people using moisturiser don't cover up as much as those using sunscreen, but suggested people tend to use more sunscreen, so it spreads further, and moisturiser perhaps isn't spread as easily.
"If planning prolonged sun exposure we advise sunscreen be used. If using moisturiser we advise one with SPF: any SPF is better than none but it should not be considered the equal of sunscreen."
Alternatively people should put on UV-filtering sunglasses, they said.
The Ministry of Health recommends using sunscreen with an SPF of at least 30, especially between September and April. Recent testing by Consumer has found many sunscreens don't offer the protection they claim, however.