Transorbital Sonography in the Evaluation of the Optic Nerve and Optic Nerve Sheath Diameter Considering Specific Demographic Features

Transorbital sonography is a reliable method for non-invasive assessment of optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) in patients with increased intracranial pressure. A wide range of regular ONSD values has been reported in the literature. The aim of this study was to determine normal values for OND and ONSD, to determine differences between OND and ONSD considering sex, age, and body mass index (BMI), and to evaluate inter - and intra - examiner variability. The study included 100 healthy subjects, aged 22 - 87 years, who underwent transbulbar sonography by the two examiners, each examiner measuring OND and ONSD twice on both eyes at a depth of 3 mm behind the optic nerve papilla. Measurement and analysis of OND and ONSD was possible in all subjects. Mean OND was 2.39 +/- 0.28 mm and mean ONSD was 4.48 +/- 0.76 mm. In males, mean OND was 2.47 +/- 0.28 mm and in females 2.35 +/- 0.27 mm (p = 0.042). There was no statistically significant difference between mean ONSD values between sexes (p > 0.001). Correlation between age and mean OND and ONSD wasn`t observed. Positive correlation between mean OND and BMI (p = 0.001) was observed. Positive correlation within and between investigator measurements (p < 0.01) was shown. Men have a wider OND compared to women, but no difference in ONSD was observed. Age doesn`t effect on the width of OND and ONSD. BMI correlates positively with OND, but not with ONSD. Positive correlation within and between investigator measurements was shown.