Quotidian Profile of Vergence Angle in Ambulatory Subjects Monitored With Wearable Eye Tracking Glasses

Abstract

Purpose Wearable eye trackers record gaze position as ambulatory subjects navigate their environment. Tobii Pro Glasses 3 were tested to assess their accuracy and precision in the measurement of vergence angle. Methods Four subjects wore the eye tracking glasses, with their head stabilized, while fixating at a series of distances corresponding to vergence demands of: 0.25, 0.50, 1, 2, 4, 8, 16, and 32°. After these laboratory trials were completed, 10 subjects wore the glasses for a prolonged period while carrying out their customary daily pursuits. A vergence profile was compiled for each subject and compared with interpupillary distance. Results In the laboratory, the eye tracking glasses were comparable in accuracy to remote video eye trackers, outputting a mean vergence value within 1° of demand at all angles except 32°. In ambulatory subjects, the glasses were less accurate, due to tracking interruptions and measurement errors, partly mitigated by the application of data filters. Nonetheless, a useful record of vergence behavior was obtained in every subject. Vergence profiles often had a bimodal distribution, reflecting a preponderance of activities at near (mobile phone and computer) or far (driving and walking). As expected, vergence angle correlated with interpupillary distance. Conclusions Wearable eye tracking glasses make it possible to compile a nearly continuous record of vergence angle over hours, which can be correlated with the corresponding visual scene viewed by ambulatory subjects. Translational Relevance This technology provides new insight into the diversity of human ocular motor behavior and may become useful for the diagnosis of disorders that affect vergence function such as: convergence insufficiency, Parkinson disease, and strabismus.

Comparative Analysis of Strabismus Measurement Using a Video Oculagraphy System and Alternate Prism Cover Test

“…As expected, given the high precision required, the correlation between automatic measurements obtained from VOG devices (such as VOG GazeLab with a correlation coefficient of 0.454 and VOG Perea with a correlation coefficient of 0.570) and APCT is considerably lower 24 . Likewise, ET devices have been validated in orthotropic subjects, showing slightly lower correlations with APCT for horizontal movements (ranging from 0.401 to 0.527) and significantly lower correlations for vertical movements (<0.034) 48 . These measurements are very useful to validate the results in a normal population, but it is completely different from our goal, which is applied to the strabismic population being the main target for assessing ocular motility.…”

“…ET and VOG are currently used in various areas associated with visual functioning, including nystagmus, 6–8 oculomotricity, 9–14 contrast sensitivity, 15 visual acuity, 15 pupillography, 16 cyclotorsion, 17,18 and primarily for detecting and/or quantifying ocular misalignment, whether it be heterophoria 19–24 or heterotropia 25–52 …”

“…In recent years, various investigations have compared the measurement of strabismus using APCT and VOG, showing that both measurements are interchangeable due to the high precision of the technology 37–52 . One of the VOG systems available is the GazeLab (BCN Innova, Barcelona, Spain).…”

“…In recent years, various investigations have compared the measurement of strabismus using APCT and VOG, showing that both measurements are interchangeable due to the high precision of the technology. [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] One of the VOG systems available is the GazeLab (BCN Innova, Barcelona, Spain). A study conducted by Narváez-Palazón et al 25 has already shown good reliability and validity in the measurement of horizontal heterophoria, but there is no research on this system that evaluates its accuracy in measuring tropias.…”

Artificial intelligence enabled smart digital eye wearables

“…Thus, orthoptic therapy for strabismus can greatly benefit from EOG-based eye tracking [43]. Wearable eye tracking has enabled the assessment of vergence in ambulatory conditions [45]. And by precisely defining the clinical features, they have quantified the severity of intermittent exotropia [46].…”