Advances in imaging of the optic disc and retinal nerve fiber layer.

In the past decade, three technologies for imaging the optic disc and retinal nerve fiber layer have become commercially available: 1) confocal scanning laser tomography with the Heidelberg retinal tomograph; 2) confocal scanning laser polarimetry with the GDx VCC; and 3) optical coherence tomography with the Stratus OCT. Each uses different principles of physics. Understanding the merits and limitations of each of these technologies requires familiarity with the principles of operation of each device. This knowledge should be considered a prerequisite for the appropriate clinical utilization of these devices and for accurate interpretation of their results.