Tear lipid supplement prophylaxis against dry eye in adverse environments

•Randomised double-masked paired-eye trial in symptomatic dry eye subjects (n=30).•Lipid and non-lipid drop instilled before simulated adverse environment exposure.•Tear film parameters measured at baseline, post-instillation and post-exposure.•Both drops prevented tear film stability from declining below baseline levels.•Lipid drop superior prophylactically at maintaining lipid layer quality. To compare the prophylactic efficacy of single application of lipid and non-lipid containing tear supplements, prior to exposure of symptomatic dry eye subjects to a simulated adverse environment. Thirty subjects with mild-to-moderate dry eye symptoms participated in the prospective, randomised, double-masked, paired-eye trial. A lipomimetic drop (Systane® Balance) was applied to one eye (randomised), and a non-lipid containing drop (Systane® Ultra) applied simultaneously to the contralateral eye. Subjects were subsequently exposed to a validated simulated adverse environment model created by a standing fan directed towards the eye, at a distance of 1m, for 2.5min. Low contrast glare acuity, lipid layer grade (LLG), non-invasive tear break-up time (NIBUT), temperature variation factor (TVF), and tear meniscus height (TMH) were evaluated at baseline, following eye drop instillation and following simulated adverse environment exposure. Both therapies resulted in increased NIBUT (both p0.05). However, only the lipomimetic drop increased LLG (p