Women who apply eyeliner on the inner eyelid may run the risk of contaminating the eye and causing vision trouble, according to research.

How eyeliner affects the eyes

According to research from the University of Waterloo, particles from pencil eyeliner can move into the eye, causing contamination and even vision problems!

Watching eyeliner

Lead researcher, Dr. Alison Ng, and her colleagues 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.

Each participant wore glitter eyeliner outside the lash line, and then on the inner lid area closer to the eye, or along the waterline.

“We noticed that the makeup migration happened quicker and was greater when eyeliner was put on the inner lid margin,” said Dr. Ng, also a post-doctoral fellow in the School of Optometry and Vision Science in the Faculty of Science at Waterloo.

They found that within just five minutes, between 15 and 30 per cent more particles moved into the eye’s tear film when subjects applied eyeliner to the inside of the lash line, compared to outside it. The makeup also moved more quickly into the eye when eyeliner was applied inside the lash line.

What’s in your eyeliner?

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.

“People who wear contact lenses are most likely to notice some problems,” said Dr. Ng. “If they have eyeliner stuck to their lenses, increasing deposits might cause vision disruption as the lens becomes cloudier.”

What can you do to prevent eye infections?

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 harbour 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,” said Dr. Ng. “With twist-up eyeliner, cut some off the end before each use. And always make sure to fully remove eye makeup before bed.”