If you apply eyeliner on your inner eyelid, you run the risk of contaminating your eye and causing vision trouble.
A researcher at the University of Waterloo recently ran a study which proved that particles from pencil eyeliner actually move into the eye.
Potential problems with eyeliner on the inner rim of the eye
Dr Alison Ng and her colleagues at the Centre for Contact Lens Research at Waterloo used video recordings to observe and compare the amount of eyeliner particles that migrated into the tear film — the thin coating protecting the eye — after applying makeup in different styles.
“We noticed that the makeup migration happened quicker and was greater when eyeliner was put on the inner lid margin,” says Dr Ng, who is also a post-doctoral fellow in the School of Optometry and Vision Science in the Faculty of Science at Waterloo.
Each participant wore glitter eyeliner outside the lash line, and then on the inner lid area closer to the eye, also known as the waterline.
The makeup migrated beyond the waterline
The vision scientists found that within five minutes, between 15 and 30 percent more particles moved into the eye’s tear film when subjects applied eyeliner to the inside of the lash line (waterline), compared to outside it. The makeup also moved more quickly into the eye when eyeliner was applied inside the lash line.
As time passes, the amount of makeup entering the tear film steadily drops and by two hours, there was a negligible amount of eyeliner left. However, Dr Ng and her colleagues say eyeliner can alter the tear film, adding to discomfort.
Eyeliner ingredients commonly include waxes, oils, silicones and natural gums to help eyeliner stick to eyelids and last for prolonged periods. It has to adhere through blinking, sweating and the secretion of natural oils.
Makeup that enters the tear film may cause discomfort for those with sensitive or dry eyes. But the eyeliner waxes and oils can also adhere to contact lenses and build up if used for more than one day. Resulting complications include irritation and redness, introduction of harmful bacteria from the eyeliner, and in some cases, eye infections or blurred vision.
Contact lens wearers might have it worse
“People who wear contact lenses are most likely to notice some problems,” says Dr Ng. “If they have eyeliner stuck to their lenses, increasing deposits might cause vision disruption as the lens becomes cloudier.”
While this study didn’t examine the bacterial aspect of makeup contamination to the eye, Dr Ng notes that previous studies do show that old eye makeup can harbor bacteria.
“If you thoroughly sharpen your pencil eyeliner before each application and get rid of the stuff that’s stuck to the end, you’ll have a fresh tip, which can help prevent infection,” says Dr Ng. “With twist-up eyeliner, cut some off the end before each use.”
Finally: “Always make sure to fully remove eye makeup before bed.”