AIM:To establish profiles of corneal diameter(CD), curvature(ACC), corneal central thickness(CCT)and investigate their correlations with refractive errors' spherical equivalent(SE), axial length(AL), anterior chamber depth(ACD)and crystalline lens thickness(LT)in black South Africans with healthy eyes. We also investigated the intercorrelation among the three corneal parameters.

METHODS:Eyes of six hundred subjects that included 305 males and 295 females(mean age: 28.15±13.1y, range: 10-66y)underwent a complete ophthalmic examination including refraction, slit lamp and ophthalmoscopy. CD and ACC were measured using the Oculus Keratograph 4(OCULUS Optikgeräte GmbH), and the CCT was measured with the iVue-100(Optovue, Inc.)optical coherence tomography. Refractive errors were assessed with the Nidek AR-310A auto-refractor and then subjective refraction. The AL, ACD and LT were measured with the Nidek US-500 A-scan ultrasound device.

RESULTS:There are no statistically significant between the parameters of the right and left eyes assessed, and therefore only the results of the right eyes are presented here. The mean corneal parameter values were: CD=11.77±0.32 mm(range=10.30-13.70 mm), ACC=7.88±0.29 mm(range=7.13-8.88 mm)and CCT=493.05±33.2 μm(range=412-590 μm). CD did not correlate with SE(r=0.05, P=0.24). However, CD was correlated significantly with AL(r=0.58, P=0.00)and ACD(r=0.63, P=0.00)but inversely correlated with LT(r=-0.40, P=0.00). There was no significant correlations between ACC and SE(r=-0.03, P=0.48). ACC correlated positively with AL(r=0.40, P=0.00). There were no significant correlations between ACC and ACD(r=0.04, P=0.56), and LT(r=-0.03, P=0.88). Also, there was no correlation between CCT and other ocular dimensions assessed. However, correlations among corneal parameters showed that CD correlated with ACC(r=0.71, P=0.00)and CCT(r=-0.68, P=0.00).

CONCLUSION:While CD correlated with AL, ACD and LT, the ACC correlated with AL. CCT did not correlate with any of the metrics studied here, suggesting that it is an independent factor unrelated to other ocular dimensions. Among corneal parameters, CD correlated with ACC and CCT.