In the present case report, visual pathway damage confirmed by retinal ganglion cell layer (GCL) damage on optical coherence tomography (OCT) in occipital lobe epilepsy was described.

A 25-year-old female with idiopathic generalized epilepsy developed visual blurring followed by a generalized seizure. On brain magnetic resonance imaging (MRI), very subtle changes of the cortex in the left parietooccipital lobe were observed. Two days after the attack, even after the disappearance of epileptiform wave on electroencephalogram (EEG), visual acuity in both eyes was 0.5 and a perimetry revealed nearly complete visual defect in both eyes. OCT showed severe thinning of GCL and mild thinning of retinal nerve fiber layer (RNFL). No additional seizure attack occurred thereafter. One month after the attack, her visual acuity was recovered to 1.0 in both eyes and her left visual hemifield defect was recovered. However, even 6 months after the attack, her right visual hemifield defect and GCL damage persisted in both eyes.

We reported a case in which the visual pathway damage caused by occipital lobe epilepsy was identified using OCT, despite very subtle changes in brain imaging. This case indicated GCL thinning is an objective and prognostic index for the irreversible visual field defect in occipital lobe epilepsy.