Eye and head movement recordings using smartphone: measurements of accuracy and precision

Abstract

Smartphones have shown promise in the measurement of eye movements. We have shown that results of a common clinical test recorded using a smartphone are comparable with measurements from clinical video-oculography goggles. The smartphone uses ARKit’s capability to acquire eye and head movement position without the need of performing a calibration as in most eye tracking devices. Here we measure the accuracy and precision of the eye and head recordings using our application. We enrolled healthy volunteers and asked them to direct their eyes, their head, or both to targets on a wall at known eccentricities while recording their head and eye movements with our smartphone application. We measured the accuracy as the error between the eye or head movement measurement and the location of each target and the precision as the standard deviation of the eye or head position for each of the target positions. The accuracy of head recordings (16% error) was overall better than the accuracy of eye recordings (28% error). We also found that the accuracy for horizontal eye movements (26% error) was better than for vertical (30% error). Precision was also better for head movement (0.9 deg) recordings than eye movement recordings (1.5 deg) and variability tended to increase with eccentricity. Our results provide basic metrics demonstrating the utility of our application in quantitative assessment of head and eye movements. It may be advisable to include a calibration recording together with any planned recording to improve the accuracy.