title: Quantification of visual function assessment using remote eye tracking in children: validity and applicability.
abstract: OBJECTIVE
  Measurements of visual and oculomotor functions are essential for providing tailored support to visually impaired children. In young or intellectually disabled children these measurements can be difficult or even impossible to perform. Recordings of orienting gaze in response to specific visual information, made with eye tracking, may offer a solution. The aim of this study was to observe and quantify eye tracking (ET)-based gaze responses to provide information about visual and oculomotor functioning, and to compare this information with standard visual function assessments (VFA).
  
  
  METHODS
  One hundred and twenty-six visually impaired children from 1-14 years underwent a VFA. Next they underwent a remote ET test. Four aspects of oculomotor control (nystagmus, fixation, saccades, pursuit) and three visual functions (visual field, contrast, colour) were selected to compare both methods. Performance was assessed (1) during VFA using standard behavioural observation and test scores and (2) after ET by observing and scoring the eye movement recordings. Validity, in terms of agreement between results, was measured by correlation analyses. From the orienting gaze responses, quantitative parameters (gain, fixation duration and directional saccades) were calculated to characterize visual performance.
  
  
  RESULTS
  Good agreement between the two test methods was found for observational assessment of oculomotor control and visual functions (correlations ranging from rs  = 0.39 to rs  = 0.69). The quantitative parameters of visual performance showed distinct results between children with and without specific functional impairments, both in children aged 1-6 and 7-14 years.
  
  
  CONCLUSIONS
  Eye tracking-based gaze recordings are a promising tool to assess oculomotor and visual performance in a communication-free manner. Calculating quantitative parameters from specific gaze responses could assist in the characterization of functional visual performance in children, independent of age. Gaze responses are a useful addition to standard VFA in clinical practice.
authors.affiliation: Vestibular and oculomotor research group, Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands.
authors.forename: Marlou J G
authors.initials: MJ
authors.lastname: Kooiker
authors.affiliation: Vestibular and oculomotor research group, Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands.
authors.forename: Johan J M
authors.initials: JJ
authors.lastname: Pel
authors.affiliation: Royal Dutch Visio, Centre of Expertise for Blind and Partially Sighted People, Huizen, the Netherlands.
authors.forename: Hélène J M
authors.initials: HJ
authors.lastname: Verbunt
authors.affiliation: Bartiméus, Diagnostic Centre for Complex Visual Disorders, Zeist, the Netherlands.
authors.forename: Gerard C
authors.initials: GC
authors.lastname: de Wit
authors.affiliation: Bartiméus, Diagnostic Centre for Complex Visual Disorders, Zeist, the Netherlands.
authors.forename: Maria M
authors.initials: MM
authors.lastname: van Genderen
authors.affiliation: Vestibular and oculomotor research group, Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands.|Royal Dutch Visio, Centre of Expertise for Blind and Partially Sighted People, Huizen, the Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: van der Steen
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D053483:Eye Movement Measurements; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D007223:Infant; D008297:Male; D009801:Oculomotor Muscles / Q000502:physiology*; D011597:Psychomotor Performance; D012371:Robotics / Q000379:methods; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*
keywords: children; gaze responses; nystagmus; oculomotor control; remote eye tracking; validity; visual function assessment; visual impairments