Numerous studies demonstrate the association between specific risk factors and dry eye. Researchers of the watershed 2007 International Dry Eye WorkShop Epidemiology Report found consistent association between dry eye and autoimmune disease, female sex, anti-cholinergic medications, androgen deficiency, older age, postmenopausal estrogen therapy, omega-3 and omega-6 fatty acids, refractive surgery, radiation therapy, vitamin A deficiency, and hepatitis C infection (Smith et al, 2007).
More than a decade later, additional studies have identified numerous other risk factors, including a group of conditions collectively known as “sleep disorders.”
Sleep disorders are a common and problematic issue in today’s society. The major categories of sleep disorders include the insomnias, sleep-related breathing disorders, hypersomnias of central origin, circadian rhythm sleep disorders, parasomnias, and sleep-related movement disorders (Thorpy, 2012). Individuals who have sleep disorders have overall higher costs for health care (Wickwire et al, 2019).
Systemic diseases and other conditions linked to sleep disorders include depression, hypertension, diabetes, obesity, and cardiovascular events (Ayaki et al, 2015).
A Link with Dry Eye Disease
Sleep disorders affect many aspects of daily living, including increased risk for dry eye. Galor et al (2018) recently reported the results of a study evaluating the association between dry eye and comorbid insomnia in patients at the Miami Veterans Affairs Hospital. The subjects completed questionnaires regarding insomnia and dry eye symptoms, including level of ocular pain, and also underwent a comprehensive evaluation of the ocular surface. Ocular pain was used as a marker for severity of dry eye. A group of control subjects who did not have dry eye went through the same testing. Insomnia complaints were higher (61%) in subjects who had high ocular pain compared to subjects who had low ocular pain (41%) and to control subjects (18%). They concluded that dry eye severity is positively associated with the degree of insomnia in a particular individual.
Ayaki et al (2015) conducted a study of 730 Japanese subjects assessing the prevalence of sleep and mood disorders in the general clinic bases of six hospitals. Subjects had one or more of the following conditions: glaucoma, bilateral cataracts, bilateral pseudophakia, or dry eye. The subjects completed the Pittsburg Sleep Quality Index (PSQI) and the Hospital Anxiety and Depression Scale (HADS). All subjects also underwent a complete ocular evaluation. The PSQI scores and HADS scores were highest (worst) in the dry eye group. They concluded that dry eye patients may be anxious, experience chronic distress or discomfort, and have a high incidence of sleep disorders.
It Doesn’t Hurt to Ask
The mounting evidence from these and other studies demonstrates a strong association between dry eye and sleep disorders. Many practitioners currently use questionnaires to aid in identifying patients who have increased risk factors for dry eye. Given credible new evidence that links dry eye to sleep disorders, it seems logical to inquire about quality of sleep in individuals who present with signs and symptoms consistent with a diagnosis of dry eye disease. CLS
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