Purpose:
We have shown that disturbances in visual function occur in patients with a tear film break-up time (TFBUT) that is less than their inter-blink interval (IBI). It is also well known that blinking is responsible for re-establishing tear film stability. This study examines the effect of a normal versus rapid blink rate on dry eye patients’ ability to complete a panel of visual function tests.
Methods:
Forty (40) patients diagnosed with dry eye completed a series of visual tasks under two conditions. In the first condition, subjects blinked freely (normal blink rate: 4-6 blinks/min); in the second condition subjects blinked every second in time with a metronome to simulate a rapid blink rate (1 blink/sec). The visual functional tasks included Best Corrected Visual Acuity (BCVA), visual search, moving target detection and reading a biographical passage. All tests were counterbalanced across patients.
Results:
BCVA, visual search and reading were significantly impaired by a rapid blink rate. The following table shows our findings -
Conclusions:
The data show that a rapid blink rate (1 blink/sec) impacts visual performance including BCVA, visual search and reading. These findings warrant further investigation of visual impairment due to rapid blinking and possible causes of this condition in patients diagnosed with dry eye.
Keywords: cornea: tears/tear film/dry eye • cornea: clinical science