Being sensitive to brightness myself, I believe the majority of what can be done about it lies outside of the game - adjusting brightness of your monitor and using some background light when sitting at the computer, i.e. not watching it in darkness. There's certain maximum brightness a monitor can deliver, it's brightness of a white page. If you adjust your monitor so you can watch white internet pages, the game can't get any brighter than that and all that remains is the contrast.