Videooculography

Videooculography (VOG) is a method for recording eye movements using video cameras, typically with infrared illumination, to estimate gaze direction and eye position. It is noninvasive and can be used with various populations, including children.

Most VOG systems track features on the eye, commonly the pupil center and a corneal reflection produced by an infrared light source. The relative position of these features is translated into gaze coordinates through a calibration procedure.

A typical workflow includes mounting a camera or cameras, ensuring adequate lighting, performing calibration with a known target grid, recording trials while the subject performs tasks, and post-processing to identify fixations, saccades, and smooth pursuit. Modern systems may combine head tracking to permit natural head movement.

Compared with older methods such as electro-oculography or scleral search coils, VOG is less invasive and easier to deploy, though it can be sensitive to lighting, eyelid occlusion, and reflections. Accuracy often ranges from fractions of a degree to about 1 degree, depending on system and setup, with sampling rates from 60 Hz to over 1000 Hz in high-end devices.

Applications include basic and clinical neuroscience, psychology experiments, ophthalmology, vestibular testing, human–computer interaction, driving and aviation research, and user-interface development.

Variations include dual-camera stereo VOG, single-camera PCCR tracking, and high-speed infrared systems. VOG data can be used alongside other modalities such as EEG or MRI in multimodal studies. Limitations include dependence on stable head position or head-tracking and susceptibility to artifacts.