sunburn
Sunglasses trick the brain into thinking it's dark and prevent it from producing a hormone that protects against sunburn, according to new research.

Emerging research is illuminating the dark side of wearing sunshades.

Sunglasses block UV light from entering the pineal gland through the optic nerves in the eyes.

This prevents the brain from sending the signal to the pituitary gland to produce melanin, the pigment that tans the skin and protects it from burning.

That's the theory of Dr. Sharon Moalem, a neurogeneticist, evolutionary biologist and New York Times' best selling author.

He discusses the theory in Chapter 3 of his book Survival of the Sickest.

"Sunglasses make the brain think it's dark and this means you're not starting the natural process of tanning," he told Express.co.uk.

"You're more likely to burn and therefore at more risk of skin cancer."

"Light in the eye is an important factor. It helps to short-circuit the body's natural defence mechanism against the sun."

Dr Moalem's theory is based on research published in the Journal of Investigative Dermatology suggesting that UV light in the eye activates the melanocyte-stimulating hormone, which makes the skin thicken and brown, protecting it from UV rays.

Professor John Hawk, melanoma expert for the British Skin Foundation, told Express he agreed that melanin production is "almost certainly diminished by sunglasses."

"I like this theory. I think it should be pushed forward for further research," added Dr. Sven Krengel, a German expert, has also been studying the possible link between sunglasses and skin cancer.

Dr Krengel published a separate paper in the Journal of Dermatology that explored the related theory that wearing sunglasses prevented people from seeking shade in bright sunlight, which he's says could also be contributing to higher rates of skin cancer.