A new study from a team of researchers from the UK and the Netherlands reports a strong prevalence of dry eye in younger patients and an apparent lower risk among individuals with high blood pressure and elevated BMI.

“One of the most interesting and worrying findings from the study was that young adults showed relatively high rates of dry eye symptoms, while a clinical diagnosis or the use of artificial tears in this group was rare,” says researcher Jelle Vehof, MD, PhD. “Studies on dry eye so far mainly focused on the elderly, and our study shows that dry eye appears to be common in the young as well, with unknown consequences. Future studies should really focus more on dry eye in the young, and on the possible role of screen use and prevention strategies.” 

The investigation also revealed some surprising associations: current smokers appeared to have a lesser incidence of dry eye, while ex-smokers had a higher rate of the condition. Since Dr. Vehof and his fellow researchers were surprised by these findings, they analyzed the association in a different cohort in the UK (TwinsUK), which replicated their study’s results.

“So, somehow, smoking appears to have a protective effect on dry eye that is reversed after people have stopped smoking. We are also the first to report that higher blood pressure is associated with less dry eye. We can only speculate about the mechanism, but both the autonomic nerve system and hormones have been shown to play a role in blood pressure regulation and lacrimation,” Dr. Vehof says.

The study included 79,866 individuals between the ages 20 and 94 who were part of the population-based Lifelines Cohort Study in the Netherlands. Overall, 9.1% of participants had dry eye disease as measured by the Women’s Health Study dry eye questionnaire.

The investigation also showed high rates of dry eye symptoms after ocular surgery, Dr. Vehof notes. Following eye surgery, including refractive laser surgery, participants were two to four times more likely to develop dry eye. “As the majority of these participants had their surgery at least several years before we measured dry eye, we believe that ophthalmologists really need to inform patients about the possibility of chronic dry eye after these procedures. This is currently neglected by most clinicians,” Dr. Vehof says.

Dry eye was also associated with comorbidities in almost all body systems, including musculoskeletal, gastrointestinal, ophthalmic, autoimmune, psychiatric, pain, functional, dermatological and atopic disorders. Investigators noted several other independent risk factors with strong associations including female sex, contact lens use, irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, keratoconus, osteoarthritis, connective tissue diseases, atherosclerosis, Graves’ disease, autistic disorder, depression, “burnout,” Crohn’s disease, sarcoid, lichen planus, rosacea, liver cirrhosis, sleep apnea, sinusitis, thyroid function and air pollution.

Investigators found no clear link between dry eye and lipid or blood glucose levels.

The population-based study on the epidemiology of dry eye is the largest and most extensive study on dry eye to date, which gave researchers the ability to detect new risk factors and clarify proposed risk factors from smaller studies, Dr. Vehof says.

Vehof J, Sneider H, Jansonius N, et al. Prevalence and risk factors of dry eye in 79,866 participants of the population-based lifelines cohort study in the Netherlands. The Ocular Surface. May 4, 2020. [Epub ahead of print].