Optic Disc Measurements in Children by Optical Coherence Tomography

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.

To determine the normative value of optic nerve indices in children and their association with ocular and demographic factors.

A cross-sectional study was conducted in 2018. Biometry was done using the Allegro Biograph, and macular indices were measured by OCT imaging.

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) mm 2 , 1.92±0.35 (1.91-1.93) mm 2 , and 0.14±0.14 (0.14-0.15) mm 3 , 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).

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.