Here’s something that I noticed when my babies needed a diaper change late at night: if I turned on the large room light, they would become more irritated, squinching their eyes and crying harder, and would subsequently have a harder time getting back to sleep.
My solution was to screw the “Itty Bitty Book Light” to the wall just above the “area of interest”. It would supply the minimum amount of light to get the job done. My baby would be less upset and would go back to sleep more easily afterward. It turns out that the lowered light level would also help me go back to sleep for the same reason. Double benefit for all concerned!