I don't know about you, but even when I could see better I had trouble with navy and black. For one thing, black does not always match other blacks. There are brownish blacks, purplish blacks and really black blacks. Just try putting them together in bright sunshine. Navy has the same problem. Purplish navy, grayish navy, greenish navy- you see what I mean? A color which would look good with black doesn't always look good with navy, and you want to make sure you wear the navy suit or the black suit, not half and half.
Some of the confusion is caused by different light sources. A fluorescent light at the office will make some colors look different than sunlight, which can make things look different than when viewed with a regular incandescent light bulb. And those low pressure sodium lights in tunnels are downright weird. Having done research into various illumination sources, I can see why they put them there- low pressure sodium lamps cost a lot less to run than fluorescent lamps, which cost less than incandescent lamps. High-pressure fluorescent lamps that you see in parking lots have a golden color, lending a tint to everything. Different color lamps make the same thing look different. There's even a name for it- a metamer is a particular color that looks different under different lamps.
Well, enough physics. Once you have decided which clothes are likely to be confused, you need a way to tell them apart in the dim light of the closet. Of course, you can memorize which clothes match, but I'll show you an easier way.
Buy some tiny safety pins- the golden kind you get with price tags when there is no good spot to use the plastic tie gun. Next, find a spot to pin the pins - a size tag or along a hem works as long as you remember where.
Decide what code you will use. In my trouble with navy and black, I used a safety pin going up and down for black because it reminded me of a tree trunk. When the pin is sideways like the surface of the sea it is blue. You can use any code you like as long as you can remember it in the morning when you're half asleep and deciding what to wear. If the pin might irritate your skin, like the ones on the back of the neck, pin it on the reverse so only the tag touches your skin. You can easily flip the tag up to see the pins or even feel them through the tag.
Another trick I use in the closet is ordering the clothes by type and color. I've been told it shows I have too much spare time, but it does help. After putting the skirts, pants, no-sleeve tops, short-sleeved tops, long-sleeved tops, vests and jackets in their sections, I put white on the left, followed by black, then red, yellow, green, blue and purple like a rainbow. Light colors go to the left of dark colors, so light blue is to the left of dark blue. This way I don't have to use pins on everything (they irritate my skin) but can tell navy from black. Navy is to the right of the red/yellow/green and black is to the left. The hardest part about this is keeping it up over time. However, if you do it while putting the clean clothes away each time, it becomes second nature.
I do the same thing in my sweater drawers. Being in the North, I have tons of sweaters. The top drawer has white and black, and the others are in order on the way down. I currently have a problem with some sweaters in drawers and some on shelves, but when I get another chest of drawers I'll have that one licked.
If you stay organized, you can find what you want without having to see well. It may sound a bit extreme, but I've lost enough things to make it worth the trouble.
Feel free to contact me with questions. I've been living with low vision for a long time and have some tricks up my sleeve. I'm just as careful about my business Winning Domain Names, so I'd love to hear from you.