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ABSTRACT
Background
Background
It has been reported that ocular volume varies between sex-, population and age groups.
Population-specific reference values for ocular volume are necessary for the diagnosis and
treatment of ophthalmic conditions.
Objectives
This study aimed to determine normative values for ocular volume in a black South African sample
and to investigate the effects of sex, age and asymmetry.
It has been reported that ocular volume varies between sex-, population and age groups.
Population-specific reference values for ocular volume are necessary for the diagnosis and
treatment of ophthalmic conditions.
Objectives
This study aimed to determine normative values for ocular volume in a black South African sample
and to investigate the effects of sex, age and asymmetry.
Method
Method
One hundred and four archived computed tomography (CT) scans of black South African adults
(54 males and 50 females) were used. Ocular volume was calculated from 3D landmarks placed
on the eyeball using the MeVisLab software, based on two commonly used mathematical
formulae, while also determined by manual segmentation of the eyeball using the Avizo software.
Basic descriptive statistics were recorded for each sex group and the variance of ocular volume
obtained using the three methods were statistically compared.
One hundred and four archived computed tomography (CT) scans of black South African adults
(54 males and 50 females) were used. Ocular volume was calculated from 3D landmarks placed
on the eyeball using the MeVisLab software, based on two commonly used mathematical
formulae, while also determined by manual segmentation of the eyeball using the Avizo software.
Basic descriptive statistics were recorded for each sex group and the variance of ocular volume
obtained using the three methods were statistically compared.
Result
Results
Males generally presented with greater ocular volumes (6 468.14 -7 210.51 mm3) compared to
females (6 183.69 – 6 837.25mm3), although it was not significant. A weak negative correlation
was observed between age and ocular volume in males based on the formula methods (p=0.02
and p=0.01 respectively) suggesting a slight decrease in ocular volume with age. There was no
significant difference noted in asymmetry of collective, males, and females samples.
Males generally presented with greater ocular volumes (6 468.14 -7 210.51 mm3) compared to
females (6 183.69 – 6 837.25mm3), although it was not significant. A weak negative correlation
was observed between age and ocular volume in males based on the formula methods (p=0.02
and p=0.01 respectively) suggesting a slight decrease in ocular volume with age. There was no
significant difference noted in asymmetry of collective, males, and females samples.
Conclusion
Conclusion
The results provide valuable reference data for black South Africans and highlight the need for a
standardised method for accurate and reliable ocular volume measurement. Ocular volume
determination from pre-defined anatomical landmarks for the calculation of ocular dimensions
was more repeatable and reliable in this study compared to the segmentation method.
The results provide valuable reference data for black South Africans and highlight the need for a
standardised method for accurate and reliable ocular volume measurement. Ocular volume
determination from pre-defined anatomical landmarks for the calculation of ocular dimensions
was more repeatable and reliable in this study compared to the segmentation method.