Measurements of Objective Cyclotorsion in a Population of Healthy Children.

Introduction: This study aimed to compare ocular torsion measurements to investigate normative objective cyclotorsion values in a population of healthy, full-term and preterm children. Materials and Methods: The participants enrolled in this study had an age range of 3-12 years and were divided into two groups, full-term (gestational age (GA) > 37 weeks) and preterm without retinopathy of prematurity (ROP) (GA ≤ 37 weeks). The disc-center-fovea angle (DFA) was used to evaluate ocular torsion using two different imaging modalities: optical coherence tomography (OCT) with a 55-degree field of view (FV) and conventional fundus photography (CFP) with a 45-degree FV. The values measured from both right and left eyes were combined to obtain a single value to compensate for the effect of head tilt during measurement. Results: A total of 86 full-term and 145 preterm children were enrolled in this study. The DFAs measured using OCT and CFP were -11.57° ± 5.27° and -12.07° ± 5.66° in the full-term group and -10.64° ± 5.40° and -11.25° ± 4.80° in the preterm group, respectively. There were no significant differences between the results obtained from OCT and CFP in the two groups (p=0.109 and p=0.512, respectively). There was a strong correlation between OCT and CFP in all patients, with a Pearson's correlation coefficient of 0.74 and an intraclass correlation coefficient (ICC) of 0.74 (both p < 0.001). Multivariate regression analysis showed that the average axial length (AXL) was associated with DFA. Conclusions: This study found a significant correlation between DFA measured using OCT and CFP, making either measurement modality feasible in pediatric populations. There was no significant difference in the DFA between full-term and preterm children. AXL demonstrated an association with the DFA.