Haidinger’s brushes

An entoptic phenomenon where the viewer perceives a faint, yellowish brushstroke pattern when viewing a polarized light source. This pattern arises from the radially arranged yellow pigment fibers in the macula lutea. Haidinger’s brushes are used to assess fixation in amblyopia. If fixation is foveal, the brushstroke pattern moves in synchrony with eye movements. However, if fixation is eccentric, the brushes appear displaced from the object being viewed.