Pseudotumor cerebri syndrome (PTCS) is characterized by raised intracranial pressure (ICP) with no neuroradiological abnormalities. Ocular ultrasound has been in use to measure optic nerve sheath diameter (ONSD), and retinal artery Doppler indices have been used for indirect assessment of ICP by pediatric intensivists. Here, we aimed to evaluate the correlation of the lumbar puncture (LP) opening pressure with the ultrasonographic ONSD and retinal resistive index (RRI) measures in patients with PTCS. And we wanted to find an answer to the following question: Can ultrasonographic ONSD measures serve as a follow-up tool in patients with PTCS? A prospective, single-center, case-control study was performed by pediatric intensive care and pediatric neurology departments. A total of 7 patients with PTCS were evaluated as patient group and 15 healthy children were evaluated as control group. The mean age of patient group was 138.8 +/- 43.7 months. The mean right ONSD was 6.7 +/- 0.5 mm and the mean left ONSD was 6.7 +/- 0.6 mm. The mean right RRI value was 0.73 +/- 0.03 and the mean left RRI was 0.73 +/- 0.09. For the patient group, ONSD and RRI values of both eyes were statistically significant higher values than for the control group. The mean LP opening pressure was 56.57 +/- 16.36 cmH(2)O. We detected strong, positive, and statistically significant correlations between the LP opening pressure and ONSD baseline measures for both the right eye (r= 0.882, p = 0.009) and the left eye (r = 0.649, p = 0.004). There was no correlation between opening pressure in LP and RRI measurements. We detected a statistically significant decrease in the right ONSD and left ONSD values and visual analog scale scores at the third-month follow-up. Our study results demonstrate that ultrasonographic ONSD measurements can be used as a noninvasive tool for assessment of the ICP at first admission and can be used as a follow-up tool in PTSC patients.