From their website-
ColorVeil adds a customizable color filter over your Desktop, Internet browser, video player, document, email, or program. You can work, play, read, write, or browse as usual.
Dyslexia / SSS
ColorVeil can help people with Dyslexia and Scotopic Sensitivity Syndrome. It applies a coloured tint across the screen, that can match the prescription from the optometrist.
ColorVeil can reduce screen brightness, even below its lowest available setting. This helps reduce eye strain, especially at night, and can save battery on notebooks and tablets.
ColorVeil lets you easily customize the color and opacity of the filter. For example, choose an Orange color filter to block out the blue light responsible for sleep deprivation.
ColorVeil makes it very easy to instantly turn the color filter on and off: simply click the ColorVeil icon in the notification area. Or press a (customizable) keyboard shortcut.
Portable & Installable
Run ColorVeil on any PC without installation: just download and unpack the ZIP archive. You can also install and deploy it across your network using the MSI setup program.
to download for FREE.