Assessment of the Human Retinal Neural Selectivity to Square Gratings’ Orientation with the Multifocal and Pattern Electroretinograms

Abstract

The retinal response to particular orientations might start a signaling cascade of events that help to modulate eye growth and respond to myopia control treatments. The purpose of this study was to investigate the retinal electrical activity in response to grids of different spatial orientations. The multifocal (mfERG) and pattern (PERG) ERG responses of nine eyes (spherical equivalent of −0.45 ± 1.15 D; mean age of 32.9 ± 7.7 years) were recorded with four grids (1.2 cpd) oriented at 60°, 90°, 120° and 180° under pupils’ dilation. The mfERG was analyzed by retinal eccentricity, quadrants and meridians with the same orientation of the grids. The response density of mfERG, the amplitudes of PERG and the implicit times of each peak from both tests were analyzed. The grid’s orientation did not evoke different implicit times in both tests. All retinal meridians showed higher response density with grids of parallel orientation to the meridian and lower response density with perpendicularly oriented grids. These differences were statistically significant in the horizontal and 60° meridians (p < 0.050). PERG response did not change with the grids’ orientations. The mfERG was sensitive to detect changes in the outer retinal activity with variations in stimulus orientation. The paradigm of meridional analysis of mfERG results might be more sensitive to orientation changes than the traditional analysis by rings, quadrants or hemifields.