Dry eye disease symptoms and associated risk factors in a Norwegian clinical cohort

BACKGROUND: The relationship between dry eye disease (DED) symptoms and different demographic, clinical and lifestyle factors remains poorly understood. Norway's cold climate and dry indoor air may accelerate tear evaporation, contributing to a very high meibomian gland dysfunction prevalence, as found in multiple studies. This suggests that environmental factors and age converge to drive evaporative dry eye as a near-universal finding in the Norwegian population. This study aimed to assess demographic, clinical and lifestyle correlates of DED symptoms, with a focus on sex-related differences and diurnal variation. METHODS: Between September 2021 and December 2023, 1044 individuals (303 males, 741 females) with symptoms of DED were enrolled at the Norwegian Dry Eye Clinic. All participants completed the Ocular Surface Disease Index (OSDI) and the Dry Eye Questionnaire-5 (DEQ-5) questionnaires, as well as an in-house, un-validated questionnaire. Clinical examinations and history-taking were conducted in a standardized manner by two experts. Associations between questionnaire scores and variables were analysed using Chi-squared tests, Kruskal-Wallis tests, Spearman correlations and logistic regression. RESULTS: Symptomatic DED above clinical cut-off levels was more prevalent in females than in males. Symptom severity was lowest in the late morning, and significant differences in both OSDI and DEQ5 scores were observed between individuals with and without reported omega-3 supplementation (with slightly higher scores in those taking omega-3). Allergies were associated with time-of-day symptom severity. Multivariable logistic regression revealed female sex, age below 65, not wearing contact lenses and refractive lens exchange surgery as significant risk factors for reporting more severe symptoms among the individuals in the database. CONCLUSIONS: Severity of dry eye symptoms in this symptomatic, clinic-based population was significantly associated with several demographic and clinical factors. Incorporating standardized timing of assessments may enhance diagnostic accuracy in both research and clinical settings for DED.