I would encourage you to have your sister take her daughter to an eyeMD. Whitening
of the pupil is concerning and needs to be examined by a professional. The whitening
occurs due to appearance of the tumor on the retina causing a change in the normal red reflex. Other diagnoses which can cause this reflex change include cataracts, glaucoma, retinal abnormalities such as colobomas, and high prescriptions [refractive errors].
Sandy T. Feldman, M.D., M.S.