Blink patterns and lid-contact times in dry-eye and normal subjects

摘要

Purpose: To classify blinks in dry eye and normal subjects into six subtypes, and to define the blink rate and duration within each type of blink, as well as the total lid-contact time/minute.Materials and methods: This was a single-centered, prospective, double-blind study of eleven?dry-eye and ten normal subjects. Predefined subjects watched a video while blinks were recorded for?10?minutes. Partial blinks were classified by percentage closure of maximal palpebral fissure opening:?25%,?50%,?75%. Complete blinks were characterized as full (>0 seconds), extended (>0.1?seconds), or superextended (>0.5?seconds). The mean duration of each type of blink was determined and standardized per minute as total lid-contact time.Results: Total blinks observed were?4,990?(1,414?normal,?3,756?dry eye):?1,809?(50.59%) partial and?1,767?(49.41%) complete blinks among dry-eye subjects versus?741?(52.90%) partial and?673?(47.60%) complete blinks among normal subjects. Only superextended blinks of ≥0.5-second duration were significantly more frequent in dry-eye subjects than normals (2.3%?versus?0.2%, respectively; P=0.023). Total contact time was seven times higher in dry-eye subjects than normals (0.565?versus?0.080?seconds, respectively; P0.1?second), the average contact time (seconds) was four times longer in dry-eye versus normal subjects (2.459?in dry eye,?0.575?in normals; P=0.003). Isolating only superextended blinks (>0.5?seconds), average contact time was also significantly different (7.134?in dry eye,?1.589?in normals; P<0.001). The contact rate for all full closures was?6.4?times longer in dry-eye (0.045?versus?0.007, P<0.001) than normal subjects.Conclusion: Dry-eye subjects spent?4.5% of a minute with their eyes closed, while normal subjects spent?0.7% of a minute with their eyes closed. Contact time might play a role in the visual function decay associated with increased blink rates.