There is also this from Columbia University
“Many people will think it’s safe to take a selfie with the eclipse in the background because they aren’t looking directly at the sun,” says Tongalp Tezel, MD, a retina expert at Columbia University Medical Center. “What they may not realize is that the screen of your phone reflects the ultraviolet rays emitted during an eclipse directly toward your eye, which can result in a solar burn.”
According to Dr. Tezel, Sir Isaac Newton suffered retinal damage after looking at the reflection of an eclipse in the surface of a pond—the archaic equivalent of the cell phone screen. Viewing the eclipse through a telescope can also damage the retina, as Galileo himself learned, because the device magnifies the sun’s harmful ultraviolet rays.