Background: The aim of this study was to analyze the occurrence of specific maternal, obstetric or neonatal factors, by performing a comparison between children with refractive error, strabismus and/or amblyopia (cases) and unaffected children (controls) in the province of Trento (North-East Italy).
Methods: In 2012-2014, 14,346 children attending the second year of nursery school were assessed through the preschool orthoptic screening scheme (covering 91% of the preschool population). Record linkage was performed between the orthoptic screening database and birth records (birth confirmation certificate database) for the corresponding birth cohorts (2008-2010), to examine specific maternal factors (age, smoking, nationality/race), obstetric factors (type of delivery) and neonatal factors (gestational age, weight at birth, Apgar Score, congenital birth defects, hospitalization at birth). The correlations were investigated using univariate and multivariate analysis in accordance with the logistic regression method.
Results: During orthoptic screening, 6.4% of children were found to have at least one refractive error, with astigmatism being the most common condition (5.1%). 1.9% of children were found to have strabismus and 1.8% amblyopia. Multivariate logistic regression analysis showed that the risk of developing a refractive error is associated with: maternal age ≥45 years, foreign nationality, vacuum-assisted delivery and neonatal weight <1500 grams. An excessive risk of strabismus was observed in children whose mother had smoked during pregnancy (adjusted OR=1.64).
Conclusions: Preschool orthoptic screening is a well-consolidated practice in the province of Trento, with adhesion values consistently over 90%. Studies of this type show the potential of record linkage between current information flows.