Monochromatic (red-free) photography and ophthalmoscopy of the peripapillary retinal nerve fiber layer.

The appearance of the peripapillary retinal nerve fiber layer (PRNFL) is crucial in the evaluation of patients with presumed optic neuropathies as well as in the differentiation of true optic disc edema from pseudopapilledema. Monochromatic (red-free) photography performed at 2 + magnification with a Zeiss fundus camera, a filter with maximum transmission at 540 nm, and Kodak Plus-X black-and-white film provides excellent PRNFL detail. Since direct ophthalmoscopy depends upon maximum illumination, which in turn depends upon increased color temperature of the light source, use of a direct ophthalmoscope with a gas-surrounded tungsten filament light source driven at 4.5 V raises color temperature sufficiently to allow practical use of monochromatic, red-free filters for optimum PRNFL evaluation.