Subnormal visual acuity and developmental screening outcomes in preschool children: a nationwide Korean health screening study

Background Early childhood visual function is closely related to cognitive, motor, language, and social development. However, population-based evidence on the association between subnormal presenting visual acuity (VA) and developmental screening outcomes in preschool children remains limited. Methods We analyzed nationwide Korean National Health Screening Program for Infants and Children data from 539,646 children with presenting VA data at both the 7th (54–60 months) and 8th (66–71 months) screening stages. Subnormal presenting VA was defined as < 0.5 in either eye. Developmental outcomes were assessed at 66–71 months using the Korean Developmental Screening Test. Multivariable logistic regression models adjusted for maternal age, delivery mode, maternal medical and psychiatric conditions, pregnancy complications, and child demographic, perinatal, anthropometric, and clinical factors. Results At 66–71 months, 24,599 children (4.6%) had subnormal presenting VA. Subnormal presenting VA was associated with higher odds of developmental screening abnormalities across all six domains, with the greatest odds for fine motor skills (OR, 2.11; 95% CI, 1.77–2.51). The Subnormal–Subnormal group (7th–8th screening stages) had the highest odds (OR range, 1.77–2.43). The Normal–Subnormal group also showed elevated odds, whereas the Subnormal–Normal group had lower odds than the Subnormal–Subnormal group. Conclusions Subnormal presenting VA was associated with developmental screening abnormalities at 66–71 months, with the strongest associations among children with subnormal presenting VA at both screening stages. Presenting VA may serve as a marker of developmental vulnerability and help identify children warranting further ophthalmologic and developmental evaluation.