Abstract
Purpose :
This study aims to demonstrate a novel technique to quantify eyelid kinematics during the blink cycle.
Methods :
Healthy volunteers were airbrush painted with a random speckle pattern on the outer surface of the upper eyelid. Recordings of voluntary, spontaneous, and reflex blinks were recorded for each patient. Reflex blinks were elicited using a puff of air applied to the imaged eye. Images from a Photron SA-X high-speed camera were analyzed in ZEISS INSPECT Correlate, a digital image correlation (DIC) software, to measure the in-plane vertical and horizontal displacements and velocities of multiple locations along the upper eyelid margin. The time duration of each blink type was calculated from the data.
Results :
Reflex blinks occur 40 percent faster than the voluntary and spontaneous blinks. Consistent patterns in the measurements were observed in the spontaneous and reflex blinks. The average maximum closing vertical velocity was 207±42 mm/s for spontaneous blinks and 492±36 mm/s for reflex blinks. The average maximum nasally directed horizontal velocity was 54±14 mm/s in the spontaneous blinks and 95±10 mm/s in the reflex blinks. The results presented were obtained from five patients with four iterations of each blink type. These ratios between maximum average velocities were consistent between blink types. The DIC approach was easily tuned to produce accurate and repeatable results.
Conclusions :
The combination of high-speed imaging and DIC analysis of blinking allows for high-quality kinematic analysis of the blink cycle for spontaneous and reflex blinks that allows for consistent results with a repeatable procedure. In the future, this approach will be applied to the kinematic and functional evaluation of blinking among patients with ophthalmic conditions that affect the blink cycle.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.