• Cross-polarized photography was used to enhance the visibility of the arcuate bundles of the retinal nerve fiber layer (NFL). A fundus camera (Zeiss) was modified to accept a linear polarizing filter in front of the flash and another polarizing filter in front of the film plane. The azimuths of the two filters were kept at right angles to one another. Cross-polarized photographs were taken of the NFL of seven normal eyes and 18 eyes with ocular hypertension. The polarizers were rotated together to obtain four different orientations, equally spaced through 90°. The manner in which visibility of the arcuate fibers was enhanced varied consistently with the orientation of the polarizing filters. Cross-polarization accentuated apparent defects in the NFL when compared with standard red-free illumination.
Sommer A, Kues HA, D'Anna SA, Arkell S, Robin A, Quigley HA. Cross-Polarization Photography of the Nerve Fiber Layer. Arch Ophthalmol. 1984;102(6):864-869. doi:10.1001/archopht.1984.01040030684019