Purpose:
Blink rate is especially important when considering an unstable tear film. The present study was performed to gain a better understanding of blink rate differences across a series of daily tasks in dry eye and control subjects, and to determine if subjects that frequently performed daily tasks associated with low blink rates exhibited increased dry eye signs and symptoms.
Methods:
Forty-five (45) dry eye and twenty-six (26) control subjects underwent four blink rate measures: reading, television watching, computer and primary gaze, as well as ophthalmic examinations including BCVA, visual function decay as measured by the interblink-interval visual acuity decay (IVAD) test, slit lamp biomicroscopy, TFBUT, corneal keratitis, conjunctival redness and corneal sensitivity assessments. Patients also completed two questionnaires. An Activities of Living questionnaire was employed to determine how often subjects perform activities associated with both low and high blink rates.
Results:
Blink rates were shown to vary across tasks with reading and computer use yielding the two lowest blink rates. Individuals with dry eye had faster blink rates during reading, television watching and computer use, than did control subjects. Primary gaze blink rate showed the highest variation. Individuals with dry eye were shown to have impaired visual function (as measured by the IVAD test) as compared to control subjects. The Activities of Living Questionnaire indicated that dry eye subjects who spent significant portions of time performing activities associated with low blink rates (reading and working on a computer) also had higher keratitis scores during office assessments compared to other dry eye subjects.
Conclusions:
The variation in blink rate between dry eye and normal subjects is demonstrated. The activities performed by dry eye patients associated with lower blink rates may contribute to pathology.
Keywords: cornea: tears/tear film/dry eye • cornea: clinical science