This cross-sectional observational study aims to evaluate the correlation of ultrasound-measured pupillary diameter and optic nerve sheath diameter (ONSD) with the Glasgow Coma Scale (GCS) in patients presenting with altered mental status (AMS) to the Emergency Department of ABVIMS & Dr. RML Hospital, New Delhi. A total of 149 adult patients will be enrolled over a period of one year following approval from the Institutional Ethics Committee. Patients will be selected based on predefined inclusion and exclusion criteria and evaluated within 6 hours of presentation.

Following clinical assessment and GCS scoring, a standardized Point-of-Care Ultrasound (POCUS) technique will be used to measure bilateral ONSD and pupillary diameter. For each parameter, three measurements per eye will be recorded, and the mean value will be used for analysis. Data including patient demographics, clinical history, GCS, and ultrasound findings will be documented using a structured proforma. The correlation between ONSD, pupillary diameter, and GCS will be analyzed using appropriate statistical methods. 

The study is expected to provide valuable insights into the use of POCUS-based ocular measurements as objective, bedside indicators of neurological function. If a significant correlation is found, these ultrasound parameters could assist emergency physicians in early triage, diagnosis, and management of patients with AMS—especially in settings where neuroimaging is delayed or unavailable. By integrating these non-invasive tools into routine emergency practice, the study hopes to improve patient care through faster and more reliable neurologic assessments.