Validity and reliability of eye tracking for visual acuity assessment in children with cortical visual impairment

• Published in: Journal of AAPOS Vol. 25; no. 6; pp. 334.e1 - 334.e5
• Main Authors: Chang, Melinda Y., Borchert, Mark S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-12-2021
• Subjects: Child; Eye-Tracking Technology; Humans; Infant; Reproducibility of Results; Vision Disorders - diagnosis; Vision Tests - methods; Visual Acuity
• ISSN: 1091-8531; 1528-3933
• DOI: 10.1016/j.jaapos.2021.07.008

Cortical visual impairment (CVI) is the leading cause of pediatric visual impairment in developed countries, but there is currently no evidence-based treatment. A method of visual assessment that captures multiple domains of visual functioning may facilitate evaluation of proposed therapies. We have developed an eye-tracking protocol that evaluates afferent, efferent, and higher-order visual parameters in children with CVI. We report its validity and reliability in assessing visual acuity.
We recruited 16 children with CVI between the ages of 12 months and 12 years. Visual acuity was assessed clinically using a previously published six-level scale of visual behavior. Grating acuity was assessed by eye tracking using forced-choice preferential looking, which was performed at baseline and 1 month for reliability testing. Validity was assessed by correlating clinical acuity with grating acuity by eye tracking.
Clinical visual acuity ranged from 3 to 6 on the six-level scale, and grating acuity ranged from 0.25 to 20 cycles per degree (logMAR 0.18-2.08). There was strong correlation between grating acuity by eye tracking and clinical acuity assessment (ρ = −0.82; P = 0.0002). Test–retest reliability was excellent, with an intraclass correlation coefficient of 0.96 (95% CI, 0.88-0.99).
Eye tracking demonstrates excellent reliability for visual acuity assessment and high correlation with clinical assessment of visual acuity in pediatric CVI. Future research is necessary to determine whether eye tracking can assess other visual and oculomotor parameters in children with CVI, a prerequisite for incorporating this technique into future clinical trials and patient care.▪