Tehran University of Medical Sciences (TUMS) Academic Journal of Surgery 2423-3218 8 4 2025 12 31 111 119 Mahnaz Mehrjouyi Dr Ali Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran Seyed Mojtaba Marashia Dr Ali Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran Samaneh Hajy Molla Rabi Department of Neurology, Dr Rajaee Hospital, Alborz University, Alborz, Iran Mohammad Ali Haji Azizi Dr Ali Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran Nima Mohammadi Afrakoti Dr Ali Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran 2025 12 17 Background: This study aimed to compare optic nerve sheath diameter (ONSD) with SOFA score, mortality, and length of stay in the intensive care unit (ICU) among patients with septic shock. Methods: An interventional study was conducted on 70 patients with sepsis admitted to the Shariati Hospital ICU.Demographic data were first recorded. Bedside ultrasonography through the upper eyelid was then performed to measure ONSD on admission and repeated on days three and six of ICU stay. Simultaneously, C- eactive protein (CRP), serum lactate levels, and SOFA scores were documented. The presence of encephalopathy was also evaluated. Statistical analyses using paired t-test and Pearson correlation were applied to examine associations between ONSD and clinical/laboratory parameters. Results: The mean age of patients was 60.42 ± 6.06 years, with 39 (54.2%) males. Encephalopathy was observed in 40 patients (55.6%). The mean ICU stay was 7.64 ± 2.40 days, and 39 patients (54.2%) died. ONSD showed a significant correlation with serum lactate, CRP, and SOFA score (p < 0.05). The maximum mean ONSD was 6.0 mm on days one and three, decreasing to 5.6 mm by day six. Conclusions: ONSD, alongside CRP, lactate, and SOFA score, may serve as useful markers for monitoring neurological status, systemic inflammation, hemodynamic improvement, and organ function in septic shock patients. These findings highlight their potential role in guiding timely ICU management, despite limitations such as sample size and demographic variability. https://ajs.tums.ac.ir/index.php/ajs/article/view/337