The only way my eyes can be "Good" is with glasses and clip on magnifiers. Nice bright light is critical too. I don't wear bifocals, but I wear plain glasses to drive and see any distance. I do have reading glasses that I wear for up close work. It's these reading glasses that I clip the magnifiers too. Before I started to use the clip on magnifiers, I was prone to carve off a few noses on Santa ornaments that I was carving. With the clip on magnifiers I learned to pay very close attention to where my knife blade makes contact with the wood. You can tell a lot about what's happening when you know what to look for. When making a cut with the knife you may see a tiny "shock wave" moving through the wood ahead of the knife blade as you make a cut. When you see this "shock wave" you may need to back off if there is a part that is ahead of the knife blade that you do not want to remove. There are several reasons for this "shock wave". Generally, the cut is too deep, and there is too much pressure being applied. If a stop cut is involved, you may have to deepen the stop cut, and continue cutting to it.
Try some magnification and real good light. You'll be surprised what you can see.