EFFECT OF PERIOCULAR HUMIDITY ON THE TEAR FILM LIPID LAYER

The purpose of this study was to determine the relationship between th e tear film and humidity by examining whether alterations in periocula r humidity influence the thickness of the tear film lipid layer. Thirt een dry eye subjects presenting with a baseline lipid layer thickness of less than or equal to 60 nm were fitted with modified swim goggles in which the right eye (OD) was exposed to conditions of high humidity and the left eye (OS) remained exposed to ambient room conditions. Th e lipid layer was monitored over a 60-min time course with goggles on and for an additional 60 min following goggle removal. The OD lipid la yer increased significantly in thickness within 5 min of exposure to c onditions of high humidity (p < 0.0001), reaching a maximum increase o f 66.4 nm after 15 min of goggle wear (p < 0.0001), This maximum incre ase to a lipid layer thickness of 120.5 nm was maintained at the 30- a nd 60-min goggle time points. No significant change was detected OS. F ollowing goggle removal, OD values declined but remained significantly elevated over the OS lipid layer thickness throughout the 60-min post goggle period, Moderate to total relief of dry eye symptoms was report ed during goggle wear and generally persisted at a reduced level for 1 -3 h following goggle removal. Increased periocular humidity results i n an increase in tear film lipid layer thickness, possibly by providin g an environment that is more conducive to the spreading of meibomian lipid and its incorporation into the tear film.