By Kelsey Moroz
What major risk factors associated with vaping—the act of inhaling a vapor created by a battery-powered device—impact eye health? Death, for starters, says Daniel Bintz, OD, a member of the American Optometric Association’s (AOA) Health Promotions Committee.
“Originally, vaping was marketed as a ‘safe’ alternative to tobacco use and even as a means to cessation, but its newness and lack of regulation has catapulted it into being the new cool thing for teens to do,” said Dr. Bintz.
But as 2019 comes to a close, vaping has seen a dramatic shift in public perception. After more than 1,000 vaping-linked illnesses and approximately 26 vaping-linked deaths,1 health officials are scrambling to get a better understanding of its health implications.
Vaping vs Smoking
Vaping’s impact on ocular health is still largely unknown, but if like the risk factors associated with smoking traditional cigarettes, vapers may face a wide range of eye issues.
“We’ve known for over 20 years that tobacco use quadruples the risk of developing macular degeneration. It also accelerates cataract formation and irritates the eyes,” said Dr. Bintz.
Nur Amalina Md Isa, MOptom, BOptom (Hons), National Institute of Ophthalmic Sciences, Lorong Utara (B), Petaling Jaya, Malaysia, agrees that there are well-documented instances of smoking’s harm to ocular health.
“Many studies have reported that smokers have shown more ocular inflammatory signs and impaired tear function and tear-producing glands compared to non-smokers,” she said. “However, not much can be said about vaping as e-cigarettes are relatively new and studies relating to e-cigarettes and the eyes are scarce.”
Vaping may not use ingredients that are publicly known to be dangerous, like tobacco, but the liquid used in vaping devices potentially introduces unstudied chemicals to the body.
“There are studies that investigated the byproducts of certain e-liquid flavorings, which found some flavorings tend to produce more free radicals than others. And free radicals are known to cause lipid and protein oxidation, which could potentially disturb the layers of the tear film and ocular tissues,” noted Amalina.
Dr. Bintz believes that as more research is conducted, it is likely that other harmful chemicals will be found in e-cigarette “juice.” However, due to the newness of vaping, it could be decades before all serious effects are discovered.
To date, it has been found that people may be exposed to toxic compounds in first-, second-, and thirdhand vaping. According to a 2017 study, it was estimated that firsthand vapers inhaled formaldehyde (up to 49 mg day–1), acrolein (up to 10 mg day–1), and diacetyl (up to 0.5 mg day–1)—all at levels exceeding U.S. occupational limits.2
One thing we know for certain are the effects of nicotine, which is present in most vaping liquids.
“Nicotine narrows blood vessels. Being mostly nerve tissue, the eye contains an amazing amount of blood vessels; narrowing them reduces oxygen and energy transportation to every tissue in the body. Contact lenses reduce oxygen flow to the cornea, adding to already narrowed vessels. Although the cornea doesn’t contain vessels, it relies on vessels in the conjunctiva for some of its oxygen,” Dr. Bintz explained.
Contact lens wearers are generally more prone to dry eyes and discomfort, so it is possible that contact lens wearers who vape may experience more of these symptoms than non-contact lens wearers. However, this cannot be confirmed without conducting a proper study.
Linking Vaping to Dry Eyes
Studies on e-cigarettes and ocular health are limited but more are emerging.
In 2019, Amalina and colleagues investigated how vaping may impact the ocular surface health of long-term users.3
“Electronic cigarettes have been widely promoted to be a ‘healthier’ alternative to conventional smoking. Some advocate that it could be a smoking cessation device due to its much less hazardous components when compared to a tobacco cigarette,” said Amalina. “I was curious how true this claim could be relating to eye health, even though the smoke coming from electronic cigarettes is visually more bothering [re: thicker fog] than conventional cigarettes.”
Ocular Surface Disease Index, noninvasive tear breakup time, fluorescein breakup time, ocular surface staining, tear meniscus height, and Schirmer test measurements were taken from 21 males who used e-cigarettes and 21 healthy nonsmokers.
In the e-cigarette group, moderate-to-severe eye dryness was indicated.
Dry eye is an issue impacting more than 16 million people.4 In recent years, more market options have focused on treating underlying deficiencies and inflammation in addition to relieving symptoms. Cyclosporine, an anti-inflammatory agent, is found in several medications at varying concentrations, including cyclosporine ophthalmic emulsion 0.05% (Restasis; Allergan, Irvine, CA) and cyclosporine ophthalmic solution 0.09% (CEQUA; Sun Ophthalmics, Cranbury, NJ). Lubricating eye drops, such as 0.2% polyacrylic acid-based artificial tears, are sold over the counter and are considered safe and effective.
Results also showed that this group experienced significant reductions in noninvasive tear breakup time, fluorescein breakup time, and tear meniscus height compared with the nonsmokers group. Interestingly, increasing the vaping voltage made dry eye symptoms and tear instability worse.
Treating the Whole Patient
For ophthalmologists, ocular health is the focus of concern regarding vaping, and it is imperative to keep abreast of new research.
“Further investigation of the eyes at the tissue and molecular levels is required to have a clearer picture on the effect of vaping on the eyes,” Amalina explained. “Some studies on e-liquid and electronic cigarette vapors have shown that they have altered immune-related genes and can be cytotoxic to embryonic stem cells and lung cells.”
According to Dr. Bintz, too much interconnectivity exists within the human body to focus solely on one area.
“[Vaping] products primarily cause problems in blood flow and oxygen use; the eye has a huge demand for both, as does the rest of the body. The body does have separate organ systems, but it’s all tied together in a very complex way,” he said.
Providers shouldn’t shy away from counseling patients on lifestyle choices, such as smoking habits, that may impact their overall health.
“All patients should be questioned on lifestyle choices, such as tobacco and vaping use. All patients, regardless of the answer, should be informed that tobacco use causes blindness and that vaping has enough unknowns, especially when juices are from non-reputable sources, and that it should be avoided,” Dr Bintz advised. “Additionally, they need to be asked if they have a desire to quit. Then take appropriate action, including discussing the 800–QUIT-NOW Quit Line.”
For more information on vaping and fact sheets to be distributed to patients, please visit the AOA’s informational fact sheet, “Smoking, Vaping, and Your Eyes,” at https://bit.ly/2Mzz4a3.
1. Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion. Outbreak of lung injury associated with e-cigarette use, or vaping. Centers for Disease Control and Prevention. October 9, 2019. Accessed on October 13, 2019. Available at: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html#latest-outbreak-information
2. Logue JM, et al. Emissions from electronic cigarettes: Assessing vapers' intake of toxic compounds, secondhand exposures, and the associated health impacts. Environ Sci Technol. 2017 Aug 15;51(16):9271-9279. doi: 10.1021/acs.est.7b00710.
3. Md Isa NA, Koh PY, Doraj P. The tear function in electronic cigarette smokers. Optom Vis Sci. 2019 Sep;96(9):678-685. doi: 10.1097/OPX.0000000000001422.
4. Farrand KF, Fridman M, Stillman IÖ, et al. Prevalence of diagnosed dry eye disease in the United States among adults aged 18 years and older. Am J Ophthalmol. 2017 Oct;182:90-98. doi: 10.1016/j.ajo.2017.06.033.