John K Jordan
I think fluorescent bulb are terrible. A ceiling full of fluorescents is worse. The problem is a broad light source is more diffuse and hides the scratches since light is coming from many angles.
I use "point source" lights, or actually, as close to points as I can get. I like small but bright LEDs, CLFs, and/or incandescent bulbs on swingarm or gooseneck fixtures. If the light is more at a glancing angle a non-diffuse light source can make a shadow in the valley of the scratch. I use these at the lathe, not only to see scratches but to judge the compound curved surfaces I'm creating.
Another thing I do to hunt for scratches: wipe the surface down with naptha. Alcohol will also work but naptha dries faster. When sopping wet the naptha will show me what the wood will look like if I use an oil finish. When "lightly" moistened or when a really wet application starts to evaporate the scratches become very visible with good lighting.
As for avoiding sanding swirls I prefer to use sanding blocks and sand with the grain by hand. But I don't make big things.
Your point about aging eyes is a good one. I use so much light in my shop that some people joke they need sun glasses. It is perfect for me. Bright light not only helps compensate for the degrading sensitivity but provides sharper vision due to the smaller aperture of the iris.