Abstract :
Background: Raised intracranial pressure (ICP) is a common manifestation of severe brain injury and measurement of
optic nerve diameter using ultrasound as a non-invasive method is increasing being use as a marker to detect raised ICP.
The aim of this study is to determine normal optic nerve sheath diameter in normal Nigerian adults. Methods: This was a
cross-sectional prospective study conducted at the radiology department on 150 normal adults over a period of ten months.
The optic nerve sheath diameter (ONSD) was measured 3mm behind the globe using 7.5 MHz linear probe placed over
the closed eyelid with subjects in supine position. Results: The mean age of the studied population was 38.69±12.85
years. The mean age of males was 42.42±15.77 years and that of females was 35.92±9.33 years. This was statistically
significant. The mean optic nerve sheath diameter was 4.20±0.38mm (range 3.91-5.2mm). The right and left mean optic
nerve sheath diameter was 4.20±0.32mm and 4.21±0.43mm respectively. The right ONSD for males was 4.21±0.41mm
while reading for the left was 4.22±0.49. Among the females the right ONSD was 4.20± 0.39mm and left was 4.21±0.48.
There was no statistical significant difference between right and left ONSD. No significant difference between males and
females ONSD. No significant correlation between ONSD, age, sex and side. Conclusion: Normal values for optic nerve
sheath diameter have been established using ultrasound in normal Nigerian adult. No significant relationship between
ONSD, age, sex, and side.
Keyword :
Adults,Normal, Optic nerve sheath diameter, Ultrasound