Welcome to the club. It only gets worse as you get older.
There are some things that will help. Here are some that come to mind.
1. If you don't have prescription glasses in your Polaroids you might want to think about getting them. Get them with bifocals with the bifocal low on the lens. You don't want them up as high on the lens as you do normal glasses. Of course you wouldn't have on your polaroids in the dark.
2. If you already wear prescription glasses then consider one of the magnifiers that clip on you hat brim. I use these a lot. You need a brim like on a baseball cap.
3. Then there is the paste on magnifiers that you apply to your glasses. I have never used these. The ones in the photo are too high for my taste. They will interfere with your waling and looking down at the trail. However, I think you can trim them to size.
4. To help with the light there are headlamps with diode lights. These will burn for a long time and give enough light to tie on flies. When you are done switch the light off. The Petzl is a great light with three light levels. The brightest light will help you get to the fishing spot in the dark.
Petzl Tikka XP Head Lamp
5. Then there are little lamps with a flexible goose neck that you put in your vest pocket. The goose neck sticks out and gives light to tie on a fly. Not as good as the head lamp for walking in the dark, There is also small flash lights that take one AAA battery. This are very compact and give good light for walking. When you want to tie on a fly you hold the flash light in your mouth. This works surprisingly good. Then there is the small light that has the bulb and battery that are wired together. One brand was called the "Cricket." You place it between your teeth and when you applied pressure with your teeth the light turns on. Or you could squeeze it between your thumb and finger and it would light. This was a throw away light when the battery died.
There is also a magnifier that hangs from a cord around your neck. The magnifier lays flat on your chest. If I remember right it also had a light. When you wanted to tie on a fly you turned the magnifier 90 degrees to your chest. So when you looked down you could see through the magnifier. This works great but it is too bulky for my taste.