Wearable eye-trackers offer exciting advantages over screen-based systems, but their use in research settings has been hindered by significant analytic challenges as well as a lack of published performance measures among competing devices on the market. In this article, we address both of these limitations. We describe (and make freely available) an automated analysis pipeline for mapping gaze data from an egocentric coordinate system (i.e. the wearable eye-tracker) to a fixed reference coordinate system (i.e. a target stimulus in the environment). This pipeline allows researchers to study aggregate viewing behavior on a 2D planar target stimulus without restricting the mobility of participants. We also designed a task to directly compare calibration accuracy and precision across 3 popular models of wearable eye-trackers: Pupil Labs 120Hz Binocular glasses, SMI ETG 2 glasses, and the Tobii Pro Glasses 2. Our task encompassed multiple viewing conditions selected to approximate distances and gaze angles typical for short-to mid-range viewing experiments. This work will promote and facilitate the use of wearable eye-trackers for research in naturalistic viewing experiments.All analyses were completed using R v3.4.0 (R Core Team 2017) , with data formatting using the dplyr package (Wickham et al. 2017) . All linear mixed effects models were performed using the lme4 package (Bates et al. 2015) , and follow-up pairwise comparisons were performed using the lsmeans package (Lenth and Others 2016) . All results plots were created using ggplot2 (Wickham 2009) , ggpubr (Kassambara 2017) , and ggsignif (Ahlmann-Eltze 2017) packages for R . Overall PerformanceThe percentage of removed outlier (>5° from target location) gaze points during preprocessing differed by eye-tracker model. Statistical comparisons revealed the mean percentage of valid gaze points for Pupil Labs (mean: 97.1%; SE: 0.9) was significantly lower than SMI (mean: 98.7%; SE: 0.4) and Tobii (mean: 98.2%; SE: 0.4) (p < 0.001; no significant difference between Tobii and SMI).However, given that all models retained > 97% of all gaze points, this difference had a negligible effect on interpretation of subsequent analyses.We first averaged across all distances and gaze angle conditions, and tested the overall relationships between eye-tracker model and accuracy, and eye-tracker model and precision. AccuracyWe fit a linear mixed effects model to test the relationship between accuracy and eye-tracker. This model included eye-tracker as a fixed effect and subject as a random effect. Eye-tracker was a significant predictor of accuracy ( F (2,78) = 7.44, p < .001) in this model. Follow-up pairwise comparisons between eye-trackers revealed that the Pupil Labs eye-tracker was significantly more accurate than SMI ( t (78) = 2.40, p < .05) and Tobii ( t (78) = 3.81, p < .001). All other comparisons were non-significant at p > .1; see Table 2 , and Fig 4.A .

BackgroundThere is a high risk for adverse outcomes in immunocompromised, neutropenic pediatric oncology patients with fever if antibiotics are not received in a timely manner. As the absolute neutrophil count is typically unknown at the onset of fever, rapid antibiotic administration for all pediatric oncology patients with fever and suspected neutropenia is critical.Local ProblemDespite efforts over the years to meet the standard of time-to-antibiotic delivery to within 60 minutes of arrival, audits revealed a prolonged and wide-ranging time-to-antibiotics in our pediatric emergency department.MethodsWe conducted a quality improvement initiative to reduce the time to antibiotic delivery for this high risk patient population. The setting was a pediatric emergency department in an academic tertiary care hospital. We assembled a multidisciplinary team to apply quality improvement methods to understand the problem, implement interventions, and evaluate the outcomes.InterventionsWe targeted delays in patient triage, delays in antibiotic ordering, delays in antibiotic choice, and delays in bedside indwelling Port-a-Cath accessing procedure. Among other interventions, we instituted three unique measures: ceftriaxone was administered to all pediatric oncology patients with suspected neutropenia and fever; a system of ordering antibiotics that was driven by the ED pharmacist obtaining a verbal order from the ED attending; and a nurse-driven order set triggered by a unique triage category which empowered nurses to access a patient’s central line, draw and send specified blood work, and deliver an intravenous antibiotic, all potentially before an ED provider sees the patient.ResultsOver a sustained 3 year period of time, the percentage of febrile oncology patients with suspected neutropenia who met the target time-to-antibiotic delivery rose from 51% to 96%. The mean time-to-antibiotic delivery fell from 58 minutes in the pre-intervention period to 28 minutes in the post-intervention period.ConclusionsThe interventions implemented by the multidisciplinary team, using quality improvement methodology, successfully improved the percentage of febrile oncology patients receiving antibiotics within 60 minutes of arrival to a pediatric emergency department.