A study published in Cornea concluded that sleep quality may play a role in the development of dry eye disease (DED), and it may indirectly aggravate anxiety and depression.
Mengliang Wu, MD, and fellow researchers cited other recent studies that found worse sleep quality or shorter sleep durations in DED patients. However, the researchers also noted a lack of controlled studies that analyze the association between sleep quality and dry eye symptoms. They pointed out that there’s an interaction between mood status and sleep quality. ‘The association between DED and sleep quality will remain unclear if no adjustment is made for mood status,” they wrote. In their study, researchers compared sleep quality and mood status in patients with DED against a control group and analyzed differences in dry eye parameters in good and poor sleepers. The researcher included a total of 106 patients examined in the study. They were compared with 50 healthy subjects who did not report any ocular surface discomfort in the previous 2 months. Patients with systemic diseases that can affect the ocular surface and/or sleep, such as diabetes mellitus, sleep apnea, and autoimmune disease, were excluded.
Dry eye-related symptoms, positive corneal staining with fluorescein, and a Schirmer I test result of less than 5 mm or a tear breakup time (TBUT) of less than 5 seconds were used to define dry eye. The most common dry eye symptoms reported by study participants were dryness, foreign body sensation, and tired eyes. Researchers assessed sleep quality with a Chinese version of the Pittsburgh Sleep Quality Index (P5Q1). Mood disorders were analyzed with the Patient Health Questionnaire for depression and with the Generalized Anxiety Disorder Scale for anxiety, both of which contain self-reported measures. The mean age in the DED group was 46.52 years, compared with 43.1 years in the control group. Eighty-five percent of DED patients were female, compared with 38% in the control group.
Taking a closer look
Patients in the DED group had a significantly higher mean PSQI global score. “According to a cutoff point for the PSQI global score that defined a poor sleeper, approximately 68% of patients with DED had poor sleep quality compared with only 40% of the control group (P=0.001),” the researchers wrote. Those with DED also graded their sleep quality more poorly than the controls. Those in the DED group had a shorter mean sleep duration and had more sleep disturbances and daytime dysfunction. Also in the DED group, 46% and 39% could be considered depressive and anxious, compared with only 1596 and 13%, respectively, in the control group.
When focusing on sleep quality in DED patients, dry eye symptom severity and meibomian gland assessment did not differ significantly between the two subgroups. However, DED patients with poor sleep quality had shorter TBUT and lower Schirmer I test scores.
A significant correlation was found between sleep quality and mood status. Dry eye symptom severity was associated with anxiety and not any other clinical parameter of DED.
Sleeping on it
One point the researchers made was that sleep quality is typically affected in older patients, regardless of their dry eye status. However, even when including age in the regression models of readjustment, they found that TBUT and Schirmer test results were significantly associated with lower sleep quality. Two theories emerged regarding the link between sleep and tear secretion. “First, short sleep duration reduces parasympathetic tone, which is believed to stimulate tear secretion. The other possibility is that sleep deprivation influences hormones, such as androgen, that are associated with DED,” the researchers wrote.
Another potential factor affecting the results is that patients who are anxious may score their DED symptoms as more severe. “An alternative explanation is that the symptoms of DED induce mood orders,” the researchers wrote.
Ophthalmologists must analyze possible DED etiology before treating patients. “The etiology may exist locally in the eye or may be due to systemic disease, but it is also very important to consider the sleep quality, mood disorders, and patients’ daily life habits,” said study co-author Yan Wang, MD. Esen Akpek, MD, found the study interesting because although mood disorders are sometimes discussed, sleep quality usually is not. However, patients sometimes mention sleep disturbances. “In general, issues of sleep are discussed more in regard to floppy eyelid syndrome,” said Francesann Eli MD, MBA.
“This study seems to suggest we need to add questions regarding sleep to our interviews surrounding dry eye.” Attention to both sleep and mental health quality could help both patients and physicians, she added. “Because dry eye is such a prevalent condition, it is easy to quickly brush past the symptoms and move these patients along without really tackling some of the more difficult and significant issues,” Dr. Ford said. The study also may bring to light the need for occasional referrals to sleep specialists for these patients, said Dr. Akpek, who has made psychiatrist referrals before with dry eye patients but not to sleep specialists. Dr. Ford’s sleep specialist referrals have been limited to floppy eyelid syndrome patients.
About the doctors
Esen Akpek, MD,
The Bendann Family Professor of Ophthalmology and Rheumatology Wilmer Eye Institute at Johns Hopkins, Baltimore
Francesann Ford, MD,
MBA Clinical and surgical director Beautiful Vision Coral Springs, Florida
Yan Wang, MD,
Department of Ophthalmology Eye and ENT Hospital of Fudan University Shanghai, China
1. Wu M, et al. Association between sleep quality, mood status, and ocular surface characteristics in patients with dry eye disease. Cornea. 2019;38:311-317.