Optic Disc Measurements in Children by Optical Coherence Tomography

Abstract

Précis: This study showed the distribution of optic disc indices in a population-based sample of Iranian children in detail. Refractive errors and biometric components are among the ocular factors that are related to these indices. Purpose: To determine the normative value of optic nerve indices in children and their association with ocular and demographic factors. Methods: A cross-sectional study was conducted in 2018. Biometry was done using the Allegro Biograph, and macular indices were measured by OCT imaging. Results: After applying the exclusion criteria, 9051 eyes of 4784 children were analyzed. The mean±SD and 95% confidence intervals (in parentheses) of vertical cup-to-disc ratio, average cup-to-disc ratio, rim area, disc area, and cup volume were 0.45±0.15(0.45–0.46) mm, 0.43±0.14 (0.42–0.43) mm, 1.46±0.25 (1.45–1.47) mm2, 1.92±0.35 (1.91–1.93) mm2, and 0.14±0.14 (0.14–0.15) mm3, respectively. Vertical cup-to-disc ratio and average cup-to-disc ratio had a positive association with intraocular pressure (IOP) (both βs=0.003), and a negative association with retinal nerve fiber layer thickness (both βs=−0.001), central corneal thickness (CCT) (both βs=−0.001), anterior chamber depth (β=−0.025 and β=−0.027, respectively), lens thickness (β=−0.034 and β=−0.032, respectively), and mean keratometry (MK) (both βs=−0.015). The average cup-to-disc ratio had a positive association with height (β=0.001). Rim area had a negative association with increased age (β=−0.008), axial length (β=−0.065), IOP (β=−0.009), and MK (β=−0.014) and a positive association with macular volume (β=0.021), retinal nerve fiber layer thickness (β=0.004), and CCT (β=0.001). Disc area had a positive association with macular volume (β=0.031) and a negative association with female sex (β=−0.037), axial length (β=−0.087), anterior chamber depth (β=−0.112), lens thickness (β=−0.059), and MK (β=−0.048). The results of generalized estimating equations showed that cup volume was smaller in girls (β=−0.009), and had a positive association with height (β=0.001), IOP (β=0.003) and negative association with CCT (β=−0.0001) and MK (β=−0.012). Conclusion: The results provided the normative values of optic disc indices in children. Demographic factors, biometric components, IOP, SBP, and retinal parameters had a significant association with optic disc indices.