Profiling eyewash usage and preferences in individuals with hay fever using a digital cross-sectional cohort study with AllerSearch.

Eye washing is a common over-the-counter, self-administered method for managing hay fever-related ocular symptoms. However, epidemiological data on eyewash users with hay fever and their characteristics are limited. This study aimed to profile eyewash usage and preferences in individuals with hay fever. This digital, cross-sectional cohort study was conducted between February 2018 and May 2020. Individuals in Japan who downloaded the AllerSearch smartphone application were included. Factors associated with eyewash and non-eyewash users among patients with hay fever were assessed using multivariable logistic regression analyses. Of the 11,284 participants, 9,041 had hay fever. Among them, 40.7% were eyewash users (43.9% used eyewash products as needed during symptom flare-ups, 24.8% used them in the morning, and 19.4% in the evening). Factors associated with eyewash use included younger age, previous psychiatric illness, history of contact lens use, current contact lens use, active smoking, higher yogurt intake, lower nasal symptom score, higher non-nasal symptom score, and dry eye symptoms. Non-use of eyewash was linked to older age, sleep duration < 6 h, lower yogurt intake, and dry eye symptoms. This study elucidated characteristics and factors associated with eyewash use among individuals with hay fever, guiding an individualized approach to treatment and public health initiatives.