The diagnostic value of optic nerve imaging in early glaucoma

In the last decade, new imaging techniques have been added to conventional fundus photography and have been evaluated for use in early glaucoma. They all measure the loss of neuroretinal rim or retinal nerve fiber layer as a correlate to glaucomatous ganglion cell and axon loss. The value of optic disc photography, planimetry, laser scanning tomography, laser scanning polarimetry, and optical coherence tomography for the diagnosis of glaucomatous eyes in a preperimetric or early perimetric stage is analyzed on the basis of sensitivity, specificity, and receiver operating characteristics (ROC) curves. It becomes clear that all these techniques allow a more or less semi-automated evaluation of the optic disc and retinal nerve fiber layer but still have their limitations in the diagnosis of a very early, preperimetric stage of the glaucoma disease.