# Ocular Ultrasonography for Acute Ischemic Stroke: A Focus on Optic Nerve Sheath Diameter and Ischemia Side Correlation

## TL;DR

This study examines whether the side of a stroke affects optic nerve sheath diameter measurements using ultrasound, finding no significant correlation.

## Contribution

The study demonstrates that ONSD measurements are consistent regardless of stroke hemisphere, simplifying clinical assessment.

## Key findings

- No significant difference in ONSD between right and left eyes in patients with right-hemispheric stroke.
- No significant difference in ONSD between right and left eyes in patients with left-hemispheric stroke.
- Measuring one eye is sufficient for ONSD assessment in acute ischemic stroke patients.

## Abstract

Background: Ultrasound devices are nowadays widely available in emergency departments (ED). In recent years, ocular ultrasonography (OUS) has become a reliable non-invasive method for detecting an enlarged optic nerve sheath diameter (ONSD), serving as a valuable indicator of elevated intracranial pressure (ICP). In stroke patients, ICP may also increase depending on the severity of the condition. This study aimed to evaluate the relationship between the side of the ischemic lesion and the ONSD using bedside OUS in patients with acute ischemic stroke.

Materials and methods: This prospective single-center cross-sectional study was conducted between July and September 2016. All patients aged 18 years and older who presented to the ED and were diagnosed with acute ischemic stroke based on diffusion-weighted imaging-magnetic resonance imaging (DWI-MRI) findings were enrolled. The ONSD was measured at 3 mm behind the globe using a 10 MHz linear transducer on the closed eyelids. Demographic data, neurologic deficits, duration of symptoms, National Institutes of Health Stroke Scale (NIHSS) score, ischemia side, and ONSD for both eyes were recorded.

Results: Sixty-seven patients were enrolled in the study. The mean±SD ONSD was observed as 4.85±0.90 mm for the right and 4.86±1.01 mm for the left. No statistically significant difference was found between the right and left ONSD values in patients with right-hemispheric stroke. This was similarly observed in patients with left-hemispheric stroke. There was no statistically significant difference between age, gender, duration of symptoms, and NIHSS score.

Conclusion: In patients with acute ischemic stroke, measuring one eye is sufficient for ONSD assessment. There is no correspondence between the ischemia side and ONSD values.