I found out about this by accident.
Another teacher happened to mention today that there is a YouTube video with some important information about eye cancer. A mother took a flash picture of her toddler. One eye had the familiar red reflection in the pupil (“redeye”), but the other eye reflected white. Shortly thereafter, she learned a white reflection in a child’s eye could be a sign of retinoblastoma, an eye cancer that affects only babies and young children. A quick trip to the doctor confirmed the diagnosis. The teacher said the child lost an eye, but his life has been saved.
This may not be the video she was talking about, but it gets the point across — https://www.youtube.com/watch?v=mTFgvPccJkQ
(It’s in multiple languages, so don’t be discouraged if you don’t understand it; just wait for English.)