Optic Nerve Sheath Diameter in Pediatric Populations: Establishing Reference Intervals and Anthropometric...

Ultrasonographic measurement of optic nerve sheath diameter (ONSD) is emerging as a noninvasive method for assessing intracranial pressure (ICP) in children. However, its practical application is limited by the lack of adequate age-specific normative data for healthy children. This study aimed to establish age-specific reference ranges for ONSD in healthy children aged 4 to 18 years and assess how anthropometric factors such as body mass index (BMI), height, and weight affect ONSD measurements.

This cross-sectional study included 150 healthy children aged 4 to 18 years, with no suspicion of increased ICP or chronic illness. ONSD was measured bilaterally using standardized transorbital ultrasonography. Anthropometric z -scores were calculated and correlations and percentile-based reference intervals were determined.

The mean ONSD was 3.67±0.50 mm, with higher values in the 11 to 18 years group compared with the 4 to 10 years group (3.80±0.45 mm vs. 3.51±0.51 mm, P <0.001). ONSD positively correlated with age, height, weight, and BMI in the overall sample. Subgroup analyses revealed that BMI was significantly associated with ONSD only in the 11 to 18 years group. The age-specific 97th percentile upper limits were 4.33 mm (4 to 10 y) and 4.40 mm (11 to 18 y).

This study provides age-specific normative reference intervals for ONSD in healthy children and shows the impact of BMI on ONSD measurements in adolescents. These findings enhance the clinical interpretation of ONSD in pediatric settings and support its integration into noninvasive ICP assessment protocols. Further multicenter studies are required to validate the reference values.