Pattern electroretinogram in anterior ischemic optic neuropathy

INTRODUCTION: Anterior ischemia optic neuropathy is defined as ischemia of the disc optic papilla nerve. The aetiology is multifactorial and causes ischemia of the optic disc and apoptosis of the nerve cells of the retina. OBJECTIVE: To study the retina of patients with anterior ischemia optic neuropathy by means of the electroretinogram pattern (PERG) to assess the function of ganglion cells of the inner layers of the retina. PATIENTS AND METHODS: We studied 12 patients referred from the Ophthalmology Department with the diagnosis of anterior ischemia optic neuropathy. The electrophysiological study consisted of PERG and PEV within 20 days of the episode. The latencies and amplitudes of the different components of the responses and the ratios of the PERG amplitudes were determined. RESULTS: No significant differences were seen in the P50 component of the PERG or the latency of the N95 component. However, statistically significant values were obtained for the amplitude N95. These differences were greater when measured from a nonlinear baseline. CONCLUSIONS: The PERG is useful for early diagnosis of patients with anterior ischaemia optic neuropathy. Measurement of the N95 is more useful when a nonlinear baseline is used. This shows dysfunction of the ganglion cells of the inner retina caused by ischaemia and retrograde degeneration of axons and cell bodies of the optic nerve.