Background: Tumors compressing the optic pathway may lead to irreversible loss of vision which may be detected by the pattern electroretinogram (PERG) because of its relation to ganglion cell function.
Methods: Eyes of 19 patients were tested shortly before and 5-10 days after tumor surgery. Visual acuity, the 30-deg visual field and the transient and steady-state pattern reversal ERG were measured.
Results: Using patterns of 1.5 x 1.2 deg there was a good correlation between the change of pre- and post-surgical visual performance and most of the pattern ERG amplitudes. For all variables tested--P50, N95- and steady-state amplitude--there was a critical value beyond which the visual outcome could be bad or favorable, whereas patients showing higher amplitudes always remained stable or improved after surgery.
Conclusion: The positive correlation between pattern ERG amplitudes and the post-surgical outcome in the case of tumors affecting the optic pathway may be helpful in predicting the outcome for these patients.