Baseline Eyeball Biometrics on Computed Tomography in Makurdi, North Central Nigeria

Variations in ocular sizes exist in the population and this may be congenital or pathological. Reference values are therefore essential in management of ophthalmic pathologies in the fields of Ophthalmology and Neurology. The aim of the study was to establish computer tomography (CT) scan reference values of ocular sizes in Makurdi, north central Nigeria. To avoid unjustifiable radiation dose, data obtained for this study was on 111 patients referred on account of other medical conditions, to the Radiology department for CT brain scan using Philip Brilliance 16. Measurements were taken at mid-ocular axial slices with maximum anterior-posterior and transverse dimensions. The mean  ± 2 SD) ocular sizes in anterior-posterior(AP) and transverse diameter(TD) for both eyes were 22.1mm ± 1.88mm and 22.9mm ± 1.20mm respectively. The right eye was 21.9mm ± 2.33mm and 22.9mm ± 1.09mm and the left eye was 22.3mm ± 1.24mm and 23.0 ± 1.30 mm in both AP and TD respectively. The measurements were slightly higher on the left. The mean ocular measurements were higher in males and were statistically significant in the transverse measurements on both sides (P<0.04). Adult eye size was attained at age group 11-20 years and subsequently at age >70 years, there was slight reduction in ocular dimensions. Established ocular sizes on CT therefore showed that males had slightly larger eyeballs in comparison to females and there was some reduction of ocular sizes with age.