You may think they're a harmless prop.
However, spooky cosmetic lenses sold at Halloween can trigger corneal infections.
Dr Parwez Hossain, Consultant Ophthalmologist at University Hospital Southampton NHS Foundation Trust, made the claim.
He made many people using the decorative lenses – worn by Little Mix's Perrie Edwards in the past – were 'largely unaware' of the hygiene risks.
These can result in blurred vision, yellow spots and painful, red or swollen eyes – especially for those who have previously undergone eye surgery.
In costume: Little Mix's Perrie Edwards is one of many celebrities who wear themed lenses
His comments come after a recent rise in severe corneal infections.
'We have just seen a great deal of people in a relationship with the elements in a corneal infection,' Dr Hossain said.
'That raises grave concern for us when it comes to an event when cosmetic lenses are popular.'
This, he says, is partly because they are not individually shaped to fit each eye.
He added that while many online retailers have their own caring for a car accident.
'It's just about any ill-effects,' he added.
Risk: The char-topper pictured without the decorative items, which can cause infections
As if that were not enough, Dr Hossain also said people should be mindful of other potential Halloween horrors.
He explained: "It may have been hard to believe, but there are many people who have had injuries in their eyes mild irritation from the contents of glow sticks.
'We have also seen the children and their eyes on a white background.
They do not make a trip to the eye casualty. '
EATING DARK CHOCOLATE IMPROVES YOUR EYESIGHT
Dark chocolate could improve one's eyesight, research suggests.
Indulging in a bar of 72 percent in a significant improvement in two of the main markers of vision, contrast sensitivity and visual acuity, according to a study published in April.
The findings from University of the Incarnate Word Rosenberg School of Optometry at San Antonio mirror previous research including a report published that suggesting dark chocolate is markedly more beneficial than milk chocolate.
Improved vision could have been improved, improved brain function and enhanced mood.
In flavanol, an organic compound found in fruits and vegetables that reduces inflammation.
Inflammation is responsible for many of the degenerative changes associated with various chronic conditions including heart disease, Alzheimer's and cancer.
Previous studies have suggested that flavanol improves blood flow in the brain and cardiovascular system in the short term, but little research has been done in its effects on vision.