 Some see the blue as solid and the yellow as interrupted, and some see it alternating between the two states.The fact that the sensation of Haidinger's brush corresponds with the visual field of the macula means that it can be utilised in training people to look at objects with their macula.People with certain types of strabismus may undergo an adaptation whereupon they look at the object of attention not with their fovea (at the centre of the macula) but with an eccentric region of the retina.