A Novel Method for Measuring Subtle Alterations in Pupil Size in Children With Congenital Strabismus

This paper analyzes a cohort of children diagnosed with congenital strabismus independent of the deviation direction, dissociated and non-dissociated, to identify anisocoria magnitude under scotopic conditions. This disease presents changes in the white matter affecting the nerve conduction in the cortical integrator, exacerbating the reflexes controlling pupil size, producing subtle changes in the pupil dimensions that are difficult to measure using current methods. The proposed indexes estimate the degree of anisocoria using the Feret diameter and the Pattern Pupil parameter. This research presents a prospective, transversal, and experimental study carried out on 168-Mexican children aged 5-15 years from Querétaro, México, diagnosed with dissociated and non-dissociated congenital strabismus. The utilized images come from videos of each patient recorded in scotopic lighting conditions (0.3 lux). The ophthalmologist measured the Feret diameters of both pupils using the ImageJ software. 11.9% of the sample group showed “Very significant,” and “Significant” degrees of anisocoria, whereas 88.1% of the sample group had “Non-significant,” and “Few significant” degrees of anisocoria. When comparing the results with those obtained using the perimeter, and the diameter, subtle variations of anisocoria were better detected using the area criterion. ANOVA experiments allowed the following: 1) dissociated and non-dissociated congenital strabismus identification using nidp index, and 2) the comparison of the anisocoria degrees identified by the nidp and Ddmm ≥0.4 mm indexes.