Study of Optic Nerve Sheath Diameter in Normal Nepalese Adults Using Ultrasound

Bidur Kc,Amit Thapa

doi:10.3126/bjhs.v3i1.19758

Abstract

Introduction: Though invasive intracranial devices are gold standard to calculate intracranial pressure (ICP); these are not without any complications. Non-invasive measurement of ICP by Ultrasonography could be a safe and portable technique.Objectives: The objective of the study was to measure and compare values of optic nerve sheath diameter of both eyes in healthy Nepalese adults.Methodology: A prospective cross-sectional study of healthy adult Nepalese volunteers was performed using a 7.5 MHz linear Ultrasound probe on the closed eyelids; optic nerve sheath diameter (ONSD) was measured 3 mm behind the globe in each eye.Results: Optic nerve sheath diameter (ONSD) of both eyes was measured in 100 healthy volunteers of age ranged from 15 to 75 years with a mean of 30.21 ± 14.05 years. There were 18 (18%) male and 82 (82%) female. ONSD for right eye ranged from 3.20 to 4.90 mm with mean of 4.10 ± 0.50 mm and left eye from 3.20 to 4.80 mm with mean of 4.22 ± 0.49 mm. P value for right and left eye ONSD (P = 0.06) and male and female (P = 0.12 and 0.85 for right and left ONSD respectively) were within normal limits. ONSD has no correlation with age (P = 0.27 and 0.27 for right and left ONSD respectively).Conclusion Mean of optic nerve sheath diameter (ONSD) is 4.10mm and 4.22 mm for right and left eye respectively. There is no statistical significant difference in mean of ONSD between right and left eye. BJHS 2018;3(1)5 : 357-360

Highlights

The op c nerve, is a second cranial nerve (CNII), derived from embryonic re nal ganglion cell
Op c nerve sheath diameter (ONSD) of both eyes was measured in 100 healthy volunteers of age ranged from 15 to 75 years with a mean of 30.21 ± 14.05 years
This study showed no sta s cally significant associa on of op c nerve sheath diameter (ONSD) between male and female (P = 0.12 and 0.85 for right and le ONSD respec vely)

Summary

Introduction

The op c nerve, is a second cranial nerve (CNII), derived from embryonic re nal ganglion cell. Known as the nerve of vision because it carries the electrical impulses from re na to brain It is myelinated nerve wrapped with three meningeal layers of which subarachnoid space is con nuous with that of the brain.[1,2,3] change in intracranial pressure (ICP) causes reflec ve change in intraorbital subarachnoid space pressure at the same me.[1,4,5]. Gold standard for ICP measurement are Invasive intracranial devices.[6,7] these devices may invite complica ons like infec on, hemorrhage and dislodgement. It cannot be performed in cases of bleeding disorders.[8,9,10] There lies the significance of measuring ICP non-invasively.[11]

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