Measurement of normal ocular volume by the use of computed tomography

Reduction or increase in ocular volume may indicate ocular pathology. Unfortunately the reference values utilized for ocular volume had been that of non-Africans. It is therefore pertinent to have a reference value of normal for Africans.

To document the computer tomography (CT) scan measured ocular volume in Benin City, which may serve as a reference for African.

The ocular volume of 200 consecutive 'normal' patients (400 eyes) who had CT scan done (using Somatom AR.T, CT scanner, and Siemens) was calculated. The dimensions were obtained at mid-ocular axial slices with maximum anterior-posterior dimension and maximum size of the eye lens.

The mean (mean ± 2 SD) ocular volume for both eyes was 5282.23 mm 3 ± 1755.13 mm 3 (right eye was 5264.26 mm 3 ± 1781.12 mm 3 ; left eye was 5300.20 mm 3 ± 1771.57 mm 3 ). The mean ocular volumes was different for either eyeball and sex (in males the right eye was 5289.80 mm 3 , left eye was 5224.31 mm 3 ; while in females the right eye was 5338.18 mm 3 , left eye was 5240.79 mm 3 ). Ocular volume correlated with the patients' ages P = 0.006 for the right eye, P = 0.008 for the left eye and P = 0.006 for total eyeball volume.

Ocular volume correlated positively with the age of the patients to about 50 years after which some reduction was observed. We noted that males had slightly larger eyeballs in comparison to females, although not at statistical significant level.