Arterial anomaly at the optic disc.

A young girl first attended for eye examination on January 8, 1953, when she was 9 years of age. The visual acuity of each eye was 6/6, there was no error of refraction, and the fundi were recorded as normal. She was again examined on January 2, 1958, at the age of 14 years, when she was complaining of defective vision in the right eye. This eye had 2-25 D sph. myopia, which accounted for the visual defect. The refraction of the left eye was still emmetropic. In the right fundus an artery pierced the lower part of the lamina cribrosa, crossed the centre of the optic disc, and joined the upper division of the central retinal artery behind its first bifurcation (Figure). No doubt this artery had been overlooked at the previous examination. With the slit lamp and Hruby lens, the contained blood column had a granular