• The brightness of the papilla in three groups of subjects (young normal subjects, elderly normal subjects, and patients with glaucoma) was measured with a photopapillometer. By employing a sensor 1.0 mm in diameter with a fundus magnification of ×2.5, it was possible to study specific sites on the rim of the papilla. Comparison of the values obtained indicated relatively little difference in the brightness of the two sites measured in the left eyes and an obvious difference in those measured in the right eyes, the temporal side being markedly brighter. This pattern persisted throughout all groups, including that of the patients with glaucoma. There was an interesting correlation between the brightness differences observed in the papilla of the subjects and the relative symmetry of the distribution of their retinal vessels.
Robert Y, Hendrickson P. Color Appearance of the Papilla in Normal and Glaucomatous EyesA Photopapillometric Study. Arch Ophthalmol. 1984;102(12):1772-1775. doi:10.1001/archopht.1984.01040031436018