Changes in first- and second-order multifocal electroretinography in idiopathic macular hole and their correlations with macular hole diameter and visual acuity

Abstract

To evaluate the first- and second-order multifocal electroretinography (mfERG) responses in patients with idiopathic macular hole, and their correlations with macular hole diameter measured by optical coherence tomography (OCT) and visual acuity. Twenty-four eyes of 24 patients with idiopathic macular hole underwent mfERG and OCT examinations. The response amplitudes and implicit times of the first- and second-order mfERG were analyzed and compared with 20 age-similar normal control subjects. Correlation analyses between visual acuity, apical and basal diameters of the macular hole, and the first- and second-order mfERG amplitudes and implicit times were performed. The first-order mfERG N1 and P1 amplitudes in the central two concentric rings were reduced in macular hole eyes compared with controls (p < 0.006). For the second-order mfERG, only the N1 mfERG amplitude was significantly reduced at ring 6 in macular hole eyes compared with controls (p = 0.030). Correlation analysis showed that apical diameter of macular hole was significantly correlated with the first-order N1 amplitude of rings 2 to 5 (p < 0.024), the first-order P1 amplitude of rings 2 to 6 (p < 0.05), as well as the second-order P1 mfERG amplitudes of rings 3 to 6 and N1 amplitudes of rings 3 to 5 (p < 0.05). LogMAR visual acuity showed significant correlation with apical diameter of the macular hole (p = 0.002), and also with the first-order P1 amplitude of ring 2 (p = 0.024). In eyes with idiopathic macular hole, reductions in first-order mfERG responses are limited to the central macula, while the second-order mfERG response abnormalities involved more of the peripheral macular region. OCT measurement of apical and not the basal diameter of macular hole correlated with the severity of retinal dysfunction assessed by both mfERG and visual acuity.