Free today (Nov. 16) Android app Bluelight Filter

[jj2me]

Via Appgratis.

Upon first opening, you should see a temporary popup that says you have the no-ads version.

I have no valid opinion yet on whether it'll help your eyes.

Note that this is one of those apps that blocks installation of non-Google Play store apps, which is similar behavior to most screen filter apps. E.g., when installing Amazon Appstore apps, you'll be stuck where the "Install" button is non-responsive. There's a setting in the app to automatically turn it off when installing apps from unknown sources, but that uses some battery. Alternatively, just toggle the app manually via the shortcut that's on the swipe-down notification bar (it's a recommended setting to have that shortcut there).