APR 22, 2021
This study attempts to clarify the association between dry eye and sleep quality using a large population-based cohort.
The cohort comprised 71,761 participants (age range 19–94 years; 59.4% female) assessed for dry eye using the Women's Health Study Dry Eye Questionnaire. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality. Demographic factors including age, sex, body mass index, education, income and health indicators including 51 possible confounding comorbidities were corrected for in the statistical analysis. These comorbidities were correlated with both dry eye and poor sleep quality and included systemic lupus erythematosus, glaucoma/ocular hypertension and chronic fatigue syndrome
Of the 8.9% of patients who were diagnosed with dry eye, 36.4% in the study group and 24.8% of control group had poor sleep quality, after correcting for age and sex. After correcting for 51 co-morbidities, dry eye was still associated with poor sleep. Patients with dry eye scored worse on all qualitative subcomponents of the PSQI. Strikingly, 44.9% of them regularly experienced poor sleep quality, similar to the rate seen in patients with obstructive sleep apnea and osteoarthritis patients. The greater the frequency of dry eye symptoms, the greater the prevalence of poor sleep quality.
While the study used a large sample size and corrected for many confounding physiological and psychological factors, only correlation could be determined and not causation. Subjects were sampled from a narrow geographic area and were overwhelmingly of Northern European ancestry. Factors such as occupation, workplace culture and family stressors, which may have a profound effect on sleep quality, were not corrected for in the logistic regression.
Patients who suffer from dry eye disease experienced a reduced quality of life, manifesting as reduced productivity at work, limitations in social engagement and difficulty in daily tasks like reading and driving. Sleep quality is not only an important dimension of quality of life but can predict adverse cardiovascular events and mortality. Thus, clinicians must investigate the causal relationship between dry eye disease and sleep quality and whether interventions can potentially improve dry eyes in severely symptomatic patients.