Leukocoria is a medical sign for a number of conditions, including Coats disease, congenital cataract, corneal scarring, melanoma of the ciliary body,[2] Norrie disease, ocular toxocariasis, persistence of the tunica vasculosa lentis (PFV/PHPV), retinoblastoma, and retrolental fibroplasia.

Because of the potentially life-threatening nature of retinoblastoma, a cancer, that condition is usually considered in the evaluation of leukocoria.

In some rare cases (1%) the leukocoria is caused by Coats' disease (leaking retinal vessels).

On photographs taken using a flash, instead of the familiar red-eye effect, leukocoria can cause a bright white reflection in an affected eye.

In this test, when a light is shone briefly through the pupil, an orange red reflection is normal.