Is there a reference for this? The link on the site only goes to another site that makes the claim. I'm very close to 40 and haven't noticed this... though perhaps the brain compensates for it.
I didn't verify it. I can tell you anecdotally that when I was 39.9 I didn't notice any issues, the change started very soon after 40. Mainly just the typical "my arms are too short" syndrome, I can still see like an eagle further than 2 feet in front of me. However, lately I've noticed in low light I have a harder time than I used to.
