Association of Refractive Error Severity, Axial Length and Digital Screen Time with Dry Eye Disease in Young Saudi Adults

Background: Dry eye disease (DED) and refractive errors are increasingly prevalent among young adults, particularly in populations with prolonged digital device use. However, the relationship between refractive error, axial length (AL), and dry eye parameters remains incompletely understood. Methods: A cross-sectional observational study was conducted among 114 young Saudi adults attending the optometry clinic of King Saud University. Participants underwent comprehensive ocular examination including refractive assessment, AL measurement, Ocular Surface Disease Index (OSDI), non-invasive tear breakup time (NI-TBUT) and tear breakup time (TBUT). Refractive error was classified into hyperopia and myopia, with further stratification by severity. Continuous variables are presented as mean ± standard deviation (SD), while categorical variables are summarized as frequencies and percentages. One-way ANOVA was performed among refractive error groups, whereas the Kruskal-Wallis H test was used for dry eye severity. Pearson's correlation, Spearman's correlation, Bonferroni-adjusted post-hoc analysis, and linear regression analysis were performed, keeping the p-value < 0.05. The study got IRB approval and adhered to the tenets of the declaration of Helsinki. Results: The mean age of participants was 23.95 ± 3.73 years, with 64.9% females. Mean daily screen-time was 9.40 ± 2.93 h. Axial length demonstrated a weak positive correlation with OSDI scores; however, it did not reach statistical significance (r = 0.174, p = 0.065). Similarly, AL was not significantly correlated with TBUT (r = -0.134, p = 0.157) or NI-TBUT (r = -0.147, p = 0.120). In contrast, screen time showed significant correlations with the OSDI scores (r = 0.650, p < 0.001), TBUT (r = -0.585, p < 0.001), and NI-TBUT (r = -0.509, p < 0.001). Dry eye severity differed significantly across refractive error groups (Kruskal-Wallis H = 18.762, p = 0.002), showing higher refractive error associated with greater dry eye severity. Multivariable regression analyses demonstrated that greater screen time was significantly associated with higher OSDI scores and shorter TBUT and NI-TBUT, whereas spherical equivalent (SE) was not independently associated with any of these dry eye outcomes after adjusting for demographic variables. Additionally, greater screen time was significantly associated with composite dry eye severity (Spearman's ρ = 0.639, p < 0.001). Conclusions: Prolonged digital screen exposure showed the most consistent association with greater dry eye severity, whereas refractive error and axial length were not independently associated with dry eye outcomes after adjustment for screen time and demographic factors. Although unadjusted differences exist across certain refractive subgroups, behavioral factors such as screen time may contribute to dry eyes. These findings support comprehensive dry eye evaluation in individuals with refractive error and prolonged digital device use.