Abstract
Purpose:
To assess differences between dry eye and normal subjects with regard to the diurnal change in blink rate and patterns, and how changes in diurnal blink might relate to the severity of dry eye signs and symptoms
Methods:
Blink data were collected using an ECG-monitoring device adapted to record myograms that correspond to blink signaling. Three electrodes were affixed to subjects each morning; subjects wore the device for 12-14 hours and were asked to perform their normal activities. Blink activity was detected using an algorithm based on recognition of the waveform corresponding to the kinematic properties of the blink signal.
Results:
At both visits, mean IBI measured during the day was higher for normal (Visit 1: 5.30±1.62; Visit 2: 5.60±1.84) than dry eye (Visit 1: 4.57±1.62; Visit 2: 4.72±1.70) subjects, but the difference was not statistically significant at either visit (Visit 1: p=0.27; Visit 2: p=0.23). However, when segmenting the day into blocks of time of 4 hours each (morning, afternoon, evening), mean IBI for normal subjects during the afternoon (5.25±1.81) and evening (5.43±2.61) was significantly longer (p=0.0189, p=0.0424 respectively) than for dry eye subjects (4.55±1.76 afternoon, 4.31±1.72 evening) at Visit 1. Diurnal worsening of central corneal staining scores at Visit 1, and diurnal worsening of temporal lissamine green staining scores at Visit 2 were significant in dry eye subjects only. Statistically significant correlations were found between the change in fluorescein corneal staining and mean IBI for both normal and dry eye groups.
Conclusions:
There are differences in blink patterns when data are collected throughout the day instead of at discrete time points in dry eye and normal subjects. Continuous blink tracking reveals significant trending with symptoms and diurnal change in blink patterns may be an appropriate surrogate for such in the study of dry eye.