The tilted disc.

Sixty tilted discs were studied by colour photography, including some by fluorescein angiography. Attention was drawn to the contracted, D-shaped outline of the scleral canal, and it was suggested that fewer fibres than normal enter the defective side of the disc. This was supported by examination of the nerve fibre layer and the discovery of field defects in 13 of the 27 eyes in which the visual fields were examined. The similarity of these features with congenital hypoplasia of the optic nerve head was noted.