Screen Utility consists of 3 can't-miss features; Pixel Test, Screenshot Helper, and Capture Screen with Cursor.
Pixel Test will help you find any dead, defective or stuck pixels in your screen. It will fill a color to your full screen so you can easily test your pixels. It will turn your screen into the following colors; White, Red, Green, Blue, Black. Click any input to change color.
Please see more detail in app store.