I wouldn't say so at all. Poor eyesight carries on smartly. Baldness. I enjoy both.
But an old story about the controller code for a surface-to-air missile comes to mind.
Someone looking at the memory allocator spots an obvious resource leak: "This code is going to crash."
The reply was that, while the point was theoretically valid, it was irrelevant, since the system itself would detonate long before resource exhaustion became an issue.
So too prostate cancer back in the day: war, famine and plague were keeping the lifespan well below the threshold of every man's time bomb.
Do you have any source for this? As someone born in the summer to a farming family with poor eyesight, I find it hard to believe that happened because I wasn't exposed to enough sun as an infant or child.
I've worn glasses since I was 2.
I just so happen to have Hyperopia with astigmatism, neither of which came from a lack of outdoor exposure. (If anything, I needed less time outside).
That's a bit of the issue I have with such a broad generalization. It's true that for some, a lack of time outdoors damaged their eyesight, it's not universally true that all or perhaps even most poor eyesight is a result of staying indoors.