BACKGROUND: Intracranial pressure (ICP) monitoring is of profound importance concerning prognosis and treatment amongchildren with traumatic brain injury (TBI). Measurements of the optic nerve sheath diameter (ONSD) are one of the methods recommendedfor ICP monitoring. In this study, we aimed to evaluate the correlation of ONSD change in brain computed tomography(CT) with pediatric Glasgow Coma Score (pGCS) in the follow-up of pediatric cases with TBI, and also to evaluate the usability of theONSD, which is the indicator of ICP.METHODS: The data of 921 pediatric patients who were admitted to the emergency department with head injury between January2016 and January 2018 were retrospectively evaluated in this study. Age, gender, trauma type, brain CT finding, pGCS, type ofintracranial hemorrhage (ICH), and isolated skull fracture (ISF) were investigated. The patients were evaluated in three groups basedon CT findings: (i) patients with parenchymal brain injury, (ii) patients with ISF, and (iii) patients with normal brain CT results. Themeasurements of ONSD were performed using CT. Whether the ONSD measurement results of the patients were compatible withthe clinical data was investigated.RESULTS: The median age of the patients was 36 months (interquartile range [IQR] = 64) and 64.2% were male. The ONSD valuesand pGCSs of the patients with parenchymal injury were found to be significantly higher than patients with ISF and normal brainCT findings (p<0.05). The pGCSs showed a significant negative correlation with the first and second measurement results of ONSD(p<0.05). In groups undergoing control brain CT, ONSD levels in the second brain CT were found to be significantly high (p<0.05).CONCLUSION: In the clinical follow-up, ONSD measurements are reliable and significant parameters when evaluated with brain CTfindings and pGCSs. We think that repeated ONSD measurements will be useful in determining possible adverse effects of secondaryinjury, as well as in determining the severity of the trauma during admission.