Measurement of the Optic Nerve Sheath Diameter

Study Overview
=================
Brief Summary
-----------------
This study is a prospective assessment of the accuracy of ocular ultrasound as a tool to measure the diameter of the optic nerve sheath and the eyeball transverse diameter in healthy adult patients presenting to the Emergency Department and have confirmatory imaging of the optic nerve as part of their clinical care.

Detailed Description
-----------------
This will be a prospective evaluation of accuracy of microconvex and linear transducers for ultrasound measurements of the ONSD and the ETD. Study population will be adult patients that present to Cleveland Clinic Akron General Emergency Department between July 1, 2022 and July 31 April 1, 2023. Patients will be identified on the Emergency Medicine Department tracking board. Patients, once identified as meeting inclusion criteria will be asked to participate in this study and full written consent will be required. All participants will have identical procedures and there will be no groups.

Official Title
-----------------
Microconvex Probe Versus Linear Probe for Measurement of the Optic Nerve Sheath Diameter

Conditions
-----------------
Optic Nerve

Intervention / Treatment
-----------------
* Procedure: Ocular Ultrasound


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion criteria: 18 years of age and older, and; Present to Cleveland Clinic Akron General's ED (Main) Have CT head and/or ocular ordered as a part of clinical care that is read as normal or no acute disease (confirmatory imaging), and; Agree to and provide written consent for participation. Exclusion criteria: Acute ocular pathology Abnormal brain and/or ocular CT History of increased intracranial pressure or optic nerve disease Not medically stable Pregnant or incarcerated Unable to consent.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Interventional Model Description: There are no groups. All subjects will have the same inclusion criteria and will have the same intervention.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Ocular Ultrasound<br>This arm includes all patients enrolled who will have an ocular ultrasound with two different probes for a total of four ultrasounds. | Procedure: Ocular Ultrasound<br>* 1. Patients presenting to the emergency department and have a normal head and/or ocular computed tomography scan will be considered for inclusion in this study. Study staff will discuss the study with the patient and obtain consent. At that point, operator will perform ocular ultrasound. Procedure will start with either the linear or microconvex probe. A single-use sterile gel packet will be used to apply gel to one closed eyelid. The probe will be placed with minimal pressure on the eye. A transverse measurement of the ONSD will be taken. In this same view the maximal transverse diameter of the eyeball will also be measured. Images of the eye with ONSD and ETD measurements will be captured. Repeat until three measurements have been obtained resulting in an average ONSD and ETD for that eye. Repeat for other eye. Switch probe and repeat on both eyes.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Primary objective is to determine the accuracy of the microconvex ultrasound transducer as compared to the linear ultrasound transducer for ultrasound measurement of the optic nerve sheath diameter compared to CT measurements. | The patient will be enrolled and be involved with the study for 15-20 minutes. At this time the research procedures will be done. | through study duration, one year is anticipated. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To determine the level of intra- and inter-rater variability for ultrasound measurement of the optic nerve sheath diameter between the two transducer types. | The patient will be enrolled and be involved with the study for 15-20 minutes. At this time the research procedures will be done. | through study duration, one year is anticipated. | 
| To determine the accuracy of the microconvex ultrasound transducer as compared to the linear ultrasound transducer for ultrasound measurement of the eyeball transverse diameter compared to CT measurements. | The patient will be enrolled and be involved with the study for 15-20 minutes. At this time the research procedures will be done. | through study duration, one year is anticipated. | 
| To determine the accuracy of the microconvex ultrasound transducer as compared to the linear ultrasound transducer for ultrasound measurement of the ONSD/ETD compared to CT measurements. | The patient will be enrolled and be involved with the study for 15-20 minutes. At this time the research procedures will be done. | through study duration, one year is anticipated. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
ocular ultrasound, optic nerve sheath diameter, ETD