Purpose. To compare the photopic negative response (PhNR) of the full-field electroretinogram (ERG) to the PhNR of the focal ERGs in detecting glaucoma. Methods. One hundred and three eyes with glaucoma and 42 normal eyes were studied. Full-field ERGs were elicited by red stimuli on a blue background. The focal ERGs were elicited by a 15° white stimulus spot centered on the macula, the superotemporal or the inferotemporal areas of the macula. Results. In early glaucoma, the areas under the receiver operating characteristic curves (AUCs) were significantly larger for the focal PhNR (0.863–0.924) than those for the full-field PhNR (0.666–0.748) (P < .05). The sensitivity was significantly higher for the focal PhNR than for the full-field PhNR in early (P < .01) and intermediate glaucoma (P < .05). In advanced glaucoma, there was no difference in the AUCs and sensitivities between the focal and full-field PhNRs. Conclusions. The focal ERG has the diagnostic ability with higher sensitivity in detecting early and intermediate glaucoma than the full-field ERG.

These results strongly suggest that the anatomical losses of retinal neurons in local areas of the retina or optic nerve head are a cause of the reduction in the amplitude of the focal photopic negative response in open angle glaucoma.

The results indicate that the PhNR may detect subclinical impairments of RGCs caused by the possible toxic effect of ICG. This finding adds to the data that BBG and TA may be safer than ICG for use during MH surgery.

A depolarizing pattern of the cone ERG responses was seen in Pro347Leu Tg rabbits. The enhancement or preservation of the ON-bipolar cell response in the ERGs contributed to shaping the waveform in the Tg rabbits. In this model, the functional alterations in the ON-pathway took place before the deterioration of cone photoreceptor function.

The lack of significant differences on the different components of the fmERGs indicates that none of the three agents was toxic to the macula. After closure of a MH, the function of the retinal ganglion cells may recover more than that of the other neural elements in the macular area.