As leukocoria ( from Ancient Greek λευκός leukos "white" and an ancient Greek κόρη Kore " pupil " - literally " white pupil " ) ( synonym: amaurotic cat's eye ) refers to a whitish illumination of the pupil. This can occur with an ophthalmoscope or on a photo with a flash light in appearance when viewing the eye. In a leukocoria the incident light is not reflected as in the healthy eye from the retina to the underlying choroid, but of diseased structures. This leads to a whitish- yellow reflection of light.

A leukocoria can occur as early as infancy, but also at any later time. It requires an immediate diagnostic evaluation, because it is associated in about 50% of cases with a retinoblastoma. Other possible causes are a cataract, a hyperplastic primary vitreous, a retinopathy of prematurity, a Coats' disease, coloboma of the vein or retinal and myelinated nerve fibers.

A lightening of the pupil hue is also produced by a cross-eyed child, caused by the reflection of extrafoveal retina and choroid skin areas. The relevant inquiry is called Brückner test.