My girlfriend has got an Ikea lamp (HÅRTE) for her desk. The lamp was either not shining to her work, or shining directly into her eyes. It took like 10 minutes in OpenScad to make a parametric model, then half an hour to print it in some old PLA, and try it on.
I wanted to print the new version in nicer material, but the model was spot on for the first time, so no need to reprint. The fit is quite loose (it wiggles a bit), but the lamp is stationary so it does not matter. If you want a better fit, customize it according to your preferences.
May your work has all the shines and no shades.