Abstract:
The purposes of this study are to generate an indigenous normogram for ocular axial lengths in a Nigerian population, determine whether there are differences in axial lengths between the right and left eye and among different adult age groups. The study will also determine whether there are differences in axial lengths between males and females and possible racial differences between Nigerians and Caucasians. This prospective, cross sectional study involving one hundred (100) Nigerian adults was carried out at Radiology Department, Jos University Teaching Hospital (JUTH), Jos, Plateau State. Convenience sampling method was used to select the subjects. Pilot study was done to determine the intra-and inter rater reliability of MRI measurement of axial length. The equipment used is a Magnetom Concerto (Siemens) 0.2Tesla MRI machine manufactured in Germany in 2007.Head coils were used as standard practice for brain and ophthalmic scans. Subjects were placed in the supine position with the scan plane parallel to the coronal plane.T2-weighted axial scans were obtained. Axial lengths of both eyes as well as the age, sex and weight of the subjects were recorded. Axial length normogram was obtained as 2.46 ± 0.13cm. Measurements of axial length were reliable within and between radiographers ( p > 0.05). There was no positive correlation with axial length of different age groups. There were no statistical significant difference with axial lengths of males and females( p=0.63) and Nigerians and Caucasians (p<0.05) . Axial length normograms for a Nigerian population will be added advantage for radiologists and radiographers in Nigeria in their practice. Measurement of axial lengths outside the normal range will likely suggest any of the eye defects.
