> What's actually different between a photon of a given frequency that enters my eye after reflecting off a surface and a photon of the same frequency that ente

> What's actually different between a photon of a given frequency that enters my eye after reflecting off a surface and a photon of the same frequency that enters my eye after being emitted from a display? One of them gives me a migraine after 5 minutes. I assume because light being reflected off a sheet of paper gets weaker, though I'm not sure how.