Newborn babies have more sensitive eye optics and a natural aversion to bright light due to underdeveloped visual systems and poor light adjustment capabilities.

“They also have, and I really want to emphasize this, they also have much more sensitive optics of the eye. So a number of people have asked me, you know, should I be exposing my baby to sunlight? You don't want to avoid sunlight, but their eyes are very sensitive, the optics of their eyes aren't quite developed so much so that you know when you look at a newborn baby and they look a little glassy-eyed and they're kind of looking through you or even a young child. A lot of people think that they're seeing you the way that you're seeing them. Hate to break it to you, but if you ever can just google visual image of a like a one month old. The optics of their eyes are so poor that you're a cloudy image. They're not seeing your fine detail. As the optics get better, then they will see you with more and more clarity. But a lot of that is clearing of the lens and some of the other aqueous features of the newborn eye, they don't see very well. But they also don't have such great ways of adjusting to bright light. And so babies have a natural aversion to bright lights.”