It’s normal to be "more sensitive" to brightness differences in the peripheral areas compared to the fovea. The fovea has more color receptors, in the other are

It’s normal to be "more sensitive" to brightness differences in the peripheral areas compared to the fovea. The fovea has more color receptors, in the other areas, there are comparatively more monochromatic receptors (brightness). The general density of the fovea is also much larger.