Photography of the retinal nerve fibre layer: an optimised procedure.

Normal and abnormal fundi were photographed at various magnifications in one and the same fundus camera, with and without 'red-free' filters and various types of black-and-white and colour films. Colour diapositive films were copied on various black-and-white negative films, with and without filters. The final negatives were evaluated under magnification with regard to resolution and contrast of detail in the nerve fibre layer. Complementary information was obtained by means of conventional resolution measurements at high and low contrast levels. The best overall results were obtained by copying colour slides obtained in unfiltered light on a new high-contrast black-and-white film (Kodak Technical Pan), with a Wratten No. 65 A filter. This simple technique produced negatives with a good definition of the nerve fibre layer, suitable as final records.