To see Haidinger's brush, start by using a polarizer, such as a lens from a pair of polarizing sunglasses. Because it is always positioned on the macula, there is no way to make it move laterally, but it can be made to rotate, by viewing a white surface through a rotating polarizer, or by slowly tilting one's head to one side. It is most easily seen when it can be made to move. It is very faint, much more so than generally indicated in illustrations, and, like other stabilized images, tends to appear and disappear. Many people find it difficult to see Haidinger's brush initially. Simulated appearance of a computer screen viewed through a polarizer, showing typical size and intensity of Haidinger's brush As a result, two different areas of the fovea can be sensitive to two different degrees of polarization. It is thought that the macula's dichroism arises from some of its pigment molecules being arranged circularly (the small proportion of circularly arranged molecules accounts for the faintness of the phenomenon.) Xanthophyll pigments tend to be parallel to visive nerves that (because the fovea is not flat), are almost orthogonal to the fovea in its central part but nearly parallel in its outer region. The size of the brush is consistent with the size of the macula. As described by the Fresnel laws, the behavior and distribution of oblique rays in the cylindrical geometry of the foveal blue cones produce an extrinsic dichroism.

Haidinger's brush is usually attributed to the dichroism of the xanthophyll pigment found in the macula lutea. Haidinger's brush may also be seen by looking at a white area on many LCD flat panel computer screens (due to the polarization effect of the display), in which case it is often diagonal. Fainter bluish or purplish areas may be visible between the yellow brushes (see illustration). The direction of light polarization is perpendicular to the yellow bar (i.e., vertical if the bar is horizontal). It typically occupies roughly 3–5 degrees of vision, about twice or three times the width of one's thumb held at arm's length. Haidinger's brushes may be seen as a yellowish horizontal bar or bow-tie shape (with 'fuzzy' ends, hence the name 'brush') visible in the center of the visual field against the blue sky viewed while facing away from the sun, or on any bright background. Many people are able to perceive polarization of light. Haidinger saw it when he looked through various minerals that polarized light. Haidinger's brush, more commonly known as Haidinger's brushes is an image produced by the eye, an entoptic phenomenon, first described by Austrian physicist Wilhelm Karl von Haidinger in 1844. Orientation varies with that of polarization of light source. Size and intensity exaggerated for clarity. Simulated appearance of Haidinger's brush for vertically polarized light.

Entoptic phenomena white screen