Measurements of peripapillary nerve fiber layer contour in glaucoma.

We developed a method to quantify the surface contour of the peripapillary nerve fiber layer from simultaneous stereoscopic videographic images. Parameters that describe this contour are defined and compared to standard optic nerve structural parameters (cup/disk ratio, disk rim area, cup volume) in three age-matched groups of patients: 52 normal controls, 79 glaucoma suspects, and 101 glaucoma patients. Greater discriminatory information was obtained from the measurements from the superior and inferior quadrants than from the measurements from the temporal and nasal quadrants. This approach helps identify new structural markers that may more closely reflect the number of ganglion cell axons in the optic nerve. Such measurements made longitudinally in living eyes will provide valuable information about the relative rates of ganglion cell death in aging and in glaucoma.