Selective loss of the photopic negative response in patients with optic nerve atrophy.

OBJECTIVE

To determine how the photopic negative response (PhNR) is altered in patients with optic nerve atrophy.

METHODS

Ten patients with optic nerve atrophy induced by compression, trauma, or inflammation were examined. There were 6 men and 4 women with a mean age of 52.4 years. Ten age-matched control subjects were examined with the same protocol. Full-field electroretinograms were recorded, and the retinal nerve fiber layer thickness surrounding the optic nerve head was measured by means of optical coherence tomography.

RESULTS

The amplitudes of the rod, maximum, cone, and 30-Hz flicker electroretinograms of the affected eyes were not different from those of the corresponding waves of the contralateral unaffected eyes or control eyes. In contrast, the amplitude of the PhNR was significantly smaller in the affected eyes than in the contralateral (P =.005) or control (P<.001) eyes. The decrease in amplitude of the PhNR preceded thinning of the retinal nerve fiber layer. There was a significant correlation between the PhNR amplitude and retinal nerve fiber layer thickness in eyes with optic nerve atrophy (r = 0.879; P<.001).

CONCLUSIONS

Selective reduction and loss of the PhNR amplitude was found in eyes with optic nerve atrophy, which suggests that the PhNR can be used to evaluate the function of ganglion cells or their axons.