Racial variations in vision.

This study determined the distributions of uncorrected visual acuity and of refractive error in representative groups of Australian Aborigines and Australians of European origin aged 20-30 years. The methodology used in this study and its verification are described in detail. As a group, the Aborigines have significantly better visual acuity than the Europeans. This was true for both monocular and binocular vision. Some Aborigines have acuities below the previous postulated threshold levels. Aborigines as a group also have the previous postulated threshold levels. Aborigines as a group also have less myopia--in particular, less high myopia--and less astigmatism than Europeans. The mean refraction for Aborigines is about half a diopter more hypermetropic than that for Europeans, although there is not an excess of high hypermetropia in Aborigines. The lack of high refractive errors suggests that the Aborigines may not possess the genes that cause abnormal axial lengths usually associated with high refractive errors in Europeans. The superior vision of the Aborigines persisted, however, when comparing groups which were essentially emmetropic. Therefore, it appears to be a true racial difference which is not explicable on the grounds of variation in refractive error but may result from finer retinal organization or better cerebral integration of visual stimuli.