You don't give us your mom's age, so assuming she has normal physical abilities (i.e. able to use a twist switch) there's lot's of good lights available.
I have limited and deteriorating vision due retina/vitreous issues as well has having been caregiver for elderly parents with somewhat limited vision so I've got specific experience to share.
I would think in terms of two lights. A headlight to read with and a walking around light for the rest of the time.
I've used headlights for many years, well before I developed my vision problems. I got a Zebralight H-30 about a month ago and it's perfect for reading, desk and bench work. The low is just right for me (you can have too much light, particularly for slick, shiny paper, etc), the click switch is fool proof and it comes on in low, which is important to me. It weighs almost nothing so the band doesn't have to be too tight. I assume the H-50, which uses an AA battery but has a twist switch would also work as well. The H-30 uses a 123 battery, but if you pick up a half dozen or so when you buy the light, they should last her a long, long time if the light is mostly used on low setting.
The other light should probably be multilevel and easily pocketable. I pretty much use a Fenix L1D now as my pocket light. It has a click switch, comes on in low but can be brightened by touches of the switch or quickly to the very brightest by a easy twist of the head. The Fenix L1T serves the same purpose and is simpler, but the low is brighter. There are many other lights that will work for this purpose.
A flood beam is most important for this type use. A spot, particularly an optical "sharp round circle" spot is almost useless. She's probably not going to use it looking for street signs.
I keep a JetU AAA (discontinued and hard to get) with a red Photon at the bedside for my "going to the bathroom without turning the lights on" light. I like the JetU because it has a memory that can be set for low to be initial level. There are also many other very good lights that will work well. Fenix has several.
One thing that helps me a lot is to have tritium "danglers", generally called Glow Rings, attached to my lights, keys and anything else I'll need to find in low light. They're expensive and kinda hard to get but very helpful. I've also taped individual trit tubes to a couple of light switches. Even got one on my little black dog so I don't step on her at night!!
It's great that you've picked up on your mom's problems and are willing to help her out. This is one of the most frustrating things I've ever experienced. If I had to choose any one sense to give up, sight would be the last one.
I apologize for all the "I" strain in this post, but hope it's OK here.