Increased tear thinning rates in smokers may increase risk of dry eye

DENVER – Researchers have found that tears evaporated 62% faster in smokers when compared to nonsmokers, according to a study presented at an academy-sponsored press conference during the American Academy of Optometry meeting.

Daniel R. Powell, OD, PhD, FAAO, told attendees that tobacco smoke contains 7,000 substances, and quite a few of them can alter the eye’s lipids or oils that typically prevent evaporation of tears.

Daniel R. Powell

“Omega fatty acids are favorite targets for alteration by substances found in tobacco smoke,” Powell said. “Hexanoyl-lysine (HEL) is a byproduct formed when omega fatty acids are broken down.”

Powell, a clinical assistant professor at the University of Houston College of Optometry, and colleagues looked at younger smokers (older smokers may have other risk factors for dry eye, he said) with a 3-year minimum history of daily cigarette smoking. The nonsmokers had to work and live in a smoke-free environment.

When comparing the 15 smokers and 14 nonsmokers, Powell and colleagues found that HEL levels were 69% greater in smokers than in nonsmokers, and tears evaporated 62% faster in smokers.

“If the tear thinning rate is fast enough, the tears can’t lubricate the eye’s surface well enough,” Powell said. “Increased thinning rates in cigarette smokers may place them at higher risk of dry eye.”

Disclosures: The researchers received Ezell and BSK research fellowships to support their research.