Optic nerve sheath diameter measurement in healthy South Iranian adults from a cross-sectional ultrasonographic study

The measurement of optic nerve sheath diameter (ONSD) is a rapid, safe, and non-invasive method for assessing increased intracranial pressure (ICP). This study aimed to determine the mean ONSD in a healthy Iranian adult population and its correlation with demographic and anthropometric factors. Given that normal ONSD values can vary based on sex, age, ethnicity, and ultrasound techniques, establishing a local reference can enhance clinical assessment. In this cross-sectional study, 100 healthy Iranian adults (mean age 38.7 ± 9.8 years; 60 females) underwent ultrasonographic examination of the left optic nerve sheath. ONSD was measured 3 mm behind the globe in two planes, and the average of these measurements was calculated. The mean axial length (AL) was 23.53 mm (SD ± 0.94), and the mean ONSD was noted at 6.3 mm (SD ± 0.42). Statistical analysis did not reveal significant correlations between ONSD and various demographic or anthropometric factors (P:0.236). This study contributes to the literature by providing local reference values for ONSD in a healthy Iranian adult population, establishing an upper limit of 6.3 mm, and highlighting the consistency of these values with international norms, thereby improving the assessment of ICP in diverse populations.