ObjectiveTo observe the full-field ERG (ff-ERG) characteristics of patients with acute regional occult outer retinopathy (AZOOR).MethodsA retrospective observational study. From June 2017 to June 2019, 62 eyes of 42 patients (AZOOR group) who were diagnosed with AZOOR in the Department of Ophthalmology of West China Hospital of Sichuan University were included in the study. All patients had no obvious localized disease on the fundus. Among 62 eyes, BCVA of 16 eyes were＜0.1, BCVA of 27 eyes were ≤0.5, and BCVA of 19 eyes were＞0.5. From June 2018 to January 2019, 40 normal volunteers (80 eyes) who attended the outpatient clinic of West China Hospital of Sichuan University and passed detailed ophthalmological examination to exclude all eye diseases including refractive errors were selected as the normal control group. All the examined eyes were tested with ff-ERG using the German Roland visual electrophysiological inspection system. The peak times and amplitudes of the waveforms induced by each response of dark adaptation 0.01 ERG, dark adaptation 3.0 ERG, dark adaptation 3.0 ERG, light adaptation 3.0 ERG, and light adaptation 30 Hz flicker ERG were recorded, respectively. The peak time and amplitude of each ff-ERG response between the two groups were compared by independent sample t test. The peak time and amplitude of each ff-ERG response between different BCVA eyes in the AZOOR group were compared by variance test.ResultsCompared with the normal control group, 0.01 ERG b wave of the dark adaptation of AZOOR group (t=3.601, －6.120), 3.0 ERG a wave and b wave of dark adaptation (t=2.627, －4.263, 3.719, －5.866), 3.0 Oscillation potential P2 wave of dark adaptation (t=－6.625), 3.0 ERG a wave and b wave of bright adaptation (t=3.762, －3.612, 3.648, －3.739) and 30 Hz flicker ERG P wave of bright adaptation (t=－3.832), all peak time of those were significantly delayed, the amplitude decreased, and the difference was statistically significant (P＜0.05). Comparison of different BCVA eyes in the AZOOR group showed that 0.01 ERG b wave amplitude of dark adaptation (F=3.950), 3.0 ERG a peak and b wave amplitude of dark adaptation (F=4.408, 4.876), oscillation potential P2 wave amplitude of dark adaptation (F=4.295), 3.0 ERG b wave amplitude of bright adaptation (F=4.344) and 30 Hz flicker ERG P wave amplitude of bright adaptation (F=4.483) of differences were statistically significant (P＜0.05). There was no statistically significant difference in waveform peak time and amplitude of the other reactions (P＞0.05). Pairwise comparison results showed that, compared with those with 0.1≤BCVA≤0.5 and BCVA＞0.5, those with BCVA＜0.1 dark adaptation to 0.01 ERG b wave, dark adaptation 3.0 ERG b wave, dark adaptation oscillation potential P2 wave, and light adaptation 3.0 ERG b wave and light adaptation 30 Hz scintillation ERG P wave amplitude were significantly reduced, and dark adaptation to 3.0 ERG a peak was significantly delayed, the difference was statistically significant (P＜0.05).ConclusionsThe ff-ERG of patients with AZOOR show delayed peak time and decreased amplitude of each response. The worse BCVA are accompanied by the more obvious decrease of each response amplitude of ff-ERG.