Different functional changes recorded in open angle glaucoma and anterior ischemic optic neuropathy.

The retinal ganglion cell exhibits two types of functional change. The difference in response appears to depend on whether or not the retrobulbar portion of the optic nerve is actively involved. This may imply differences in the myelinated and non-myelinated portions of the optic nerve and associated structures. In open angle glaucoma, alterations in the sustained- and transient-like functions but not in the flashing repeat static test are found. That is, there are changes in spatial neural interactions, but there is no evidence of a visual fatigue or saturation-like effect. In optic nerve radiation damage without evidence of retinal vascular changes, in optic neuritis secondary to multiple sclerosis, chiasmal lesions, and ischemic optic neuropathy (considered here) varying degrees of visual fatigue or saturation-like effects are demonstrated with little or no change in the sustained- or transient-like functions.