Haidinger’s brushes

Haidinger’s brushes are an entoptic phenomenon of the macula. Yellowish, brushlike shapes seem to radiate from the point of fixation as the patient views polarized light, preferably blue light.^1,2 With central fixation the center of the brushes lies on the fixation point, and with eccentric fixation the brushes appear away from the fixation point.^1,2

The nerve fiber layer of Henle lies in a radial pattern over the macular rods and cones, and its birefringent fibers act like a yellow radial polarizing filter.² A brush appears when the plane of polarization changes and then fades like any stabilized retinal image.² A Haidinger’s brush apparatus places a blue filter and a rotating linear polarizer over a light bulb.²

Haidinger’s brushes were first used to assess the anatomical integrity of the fovea, and pleoptics later applied them to the diagnosis and treatment of eccentric fixation in amblyopia.^1,2 Fixation testing with Haidinger’s brushes is no longer in common clinical use.³