[Pete]

To "improve" your night vision you need to practice. You need to get out away from the night lights and move around. And then sit down and listen while you scan the area around you.

When you hear a sound look in that direction and then scan around the area with your eyes. Never stare right at the sound because you'll end up looking at a black spot. You pick up movement better in the areas off to each side. The medics can cover the "rods and cones details".

If you need corrective glasses wear them. You need 20/20 at night. Without glasses the grays and blacks run together and you have lost all ability to pick out detail. They help with small branches and twigs also.

When walking you need to continue to scan the area and path you are walking. Some focus so hard on "right in front" of them that they get that blacked out spot and start tripping over logs.

And like your mother said "Eat your carrots."