Optimal optokinetic parameters to distinguish young children with abnormal comprehensive eye exams from normals

Abstract

Purpose :
Measurement of vision and detection of vision disorders in preverbal children is challenging. Optokinetic nystagmus (OKN), is an early reflexive visual response, with saccadic and pursuit eye movements that can be measured over a range of spatial frequencies. OKN response may distinguish children with a risk of vision abnormality from normals, but optimal parameters and cut-points for detection are not known.

Methods :
69 children from 9 to 36 months of age (mean 19.7 +9.4), had comprehensive eye examinations (CEE) to determine presence or absence of ocular or visual disorders. Subjects were tested with Vifant VISTA OKN binocularly and monocularly. Vifant VISTA uses OKN stimulus of black and white gratings varying in 4 increments from 0.2 - 2.4 cycles per degree (CPD) for 5 seconds each, at a rate of 10 degrees per second at 44 cm, using a commercial tablet computer screen and video capture. Trained video readers quantified pursuit and saccadic eye movements. Cut-points of response parameters (number of saccade and pursuit movements detected at each spatial frequency) for three age groups (<12 months, 13-24 months, and 25-36 months) were considered for calculating sensitivity and specificity for detection of abnormal CEE.

Results : 43 children had no abnormality, and 26 (37.7%) had abnormality on CEE. Optimizing sensitivity at 80% or greater, specificity of 31-50% was achieved using either pursuit or saccade movements, using >0, >1, >2, and >3 movements in each age group, when testing monocularly (Table 1) or binocularly (Table 2). Specificity of 34-53% was achieved using total movements with all stimulus frequencies (Tables 1, 2). Combining pursuit and saccadic measurements did not improve specificity substantially.

Conclusions :
Age-specific cut-points of OKN parameters across a range of spatial frequencies demonstrated moderate specificity, when optimizing sensitivity to > 80%. OKN response at frequencies below visual threshold differentiated children with abnormal CEE. Models using OKN responses across a range of spatial frequency may be the most effective to identify children at risk for vision disorders.

This is a 2020 ARVO Annual Meeting abstract.