If a baby comes out, do they check their eyes right away? And if so, how? And how often should they check, and what kind of information is there? Yeah, that's a great question. It's obviously something that touches us all. So the answer to that really differs a little bit at the different stages of life.

First of all, every baby gets an eye exam, or should be getting an eye exam. And one of the main things that you really just are screening for right when that baby is born, right in the nursery, right in those first few days, is to just look for a red reflex.

You know when you take a camera picture, a flash picture, and sometimes you get red eye? That's actually the light from the flash, as you know, reflecting against the retina and coming back out of your eye, it looks red. And a red reflex is actually very normal. That's great.

And if you have one of a number of diseases in the eye that can present even in babies, even in newborn babies, including most concerning, but thankfully least common, retinoblastoma, which is the most common pediatric eye cancer, which again, thankfully, is quite rare, those babies won't have a red reflex in that eye.

It'll be kind of a whitish or gray reflex. And so even just that first little, you know, doctors taking the little pen light and even just flashing it in the baby's eyes. So that's our first eye exam. And hopefully we've all had that. And hopefully every baby being born today is getting that first eye exam, is really just looking for that red reflex.

It's not typical, as long as that's looking good, to worry about getting an eye exam. From there, kind of through childhood, like maybe early elementary school, unless your baby is presenting with one of a number of features that parents often pick up on. For example, as the baby's aging through those first couple of years, you know, through the first couple of years, babies actually don't have great visual acuity.

And so as they're aging over those first couple of years, it's normal for them to have, you know, roving eye movements, for example, be searching their environment. But over those first couple of years, if parents start noticing the baby isn't, you know, isn't making eye contact or looking where a sound is, certainly if they have what's called nystagmus, like these rapid flickering alternating eye movements, anything like that, of course, you're going to trigger an eye exam.

But otherwise, most babies, other than their pediatrician doing that red reflex check when they're in for their regular well child checks, that's really all that's needed through that. When most kids get to elementary school age, there will often be, often done at the schools, an amblyopia screening exam. If kids' eyes, either if one eye doesn't see that well, like maybe you're very nearsighted or farsighted in one eye and pretty normal sighted in the other, or the two refractive errors are quite different from each other, that can lead to a condition you've talked about on the podcast before called amblyopia, which is probably one of the more common or most common eye diseases of children.

Or if the eyes aren't aligned, you know, our eye muscles and the brain behind them are really responsible for keeping the two eyes looking straight ahead. And if that's not working properly and one eye is off kilter and therefore the image of what we're looking at is falling on different spots of the retina, it's not syncing up right in the brain, that can lead to this disease condition called amblyopia where that eye is no longer talking to the brain properly.

And there's a pretty easy screening exam that can be done for strabismus, the misalignment of the eyes that kids will do in elementary school. The other main presenting symptom of kids in elementary school is when they admit to their parents, I can't see the board or I can't see the teacher up front, and then they might be quite nearsighted.

And so that will also trigger an exam. And so those are usually the parts for babies, for toddlers, for children, school aged children that might reasonably trigger an exam. A couple of questions about early eye exams and we'll get onto eye exams in older individuals in a second. But I want to interrupt you with this question.

So you mentioned that there can be a misalignment of the eyes. I've seen many people's babies where there is one eyeball that seems to be kind of drifting around and then it might correct, but sometimes they'll have a, we don't want to get technical here for our listeners, we'll keep it general, but either convergent eyes or one eye converging cross eyes or wall-eyed, again, using that non-technical language here.

And my understanding is that the brain is taking that information in and is very plastic. It's changing at these early stages of development and that it's fairly critical to get that stuff corrected early on, because if you wait too long, the brain can essentially become blind to the, or rather the brain cannot learn to handle the proper alignment.

So in other words, if a kid has cross eyes, crossed eyes, excuse me, and they're not corrected until they're 20s, it's possible that they will never recover normal vision. Whereas if you recover, if you align the eyes properly early in development, they can indeed recover vision. How early can and should one consider getting those eye realignments done?

Yeah. Yeah. Pretty much right on. What they'll do is if they detect any eye misalignment, and sometimes parents are good at noticing that, and sometimes you take a picture and one eye got the red eye reflex and the other one didn't, and sometimes people notice that their kid's eyes are sort of turning in, it seems like too much.

Sometimes there's what's called pseudostrabismus, which is where actually, depending on your anatomy, if you have a little extra skin sort of on the inside corners of your eyes, it makes your eyes look turned in when actually they're straight. But if your eyes are actually turned in, or slightly less common in children, more common in adults, misalignment turned out, it's really important to correct that early.

And the reason is, as you were saying, the brain starts ignoring it. It fails to fully develop the strong connections for the data coming in from one of those two eyes into the brain. And if you pass certain sort of thresholds during development, during childhood, without correcting that connectivity, getting those two eyes to work together properly, you can permanently lose that.

And so we used to use very sort of gross numbers, like it's fully correctable if you can intervene before age three. It's partly correctable if you can intervene before age six. You got a chance before age nine. But it turns out in follow-on studies that even kids into their young teens have a shot at correcting that eye-brain connection, that amblyopia, that loss of vision that can occur during early development.

So even if you're only unfortunately detecting that later on in childhood, or even sort of the tween years, or early teen years, it's still worth a try to really push to retrain the weaker eye and then also realign the muscles so that they can work together to keep the eyes focused.

I'll tell you, it's interesting, and there's a lot more to learn about brain plasticity and probably a lot of really cool new therapies yet to discover that could reopen what's called critical period plasticity, this plasticity that we have during development that kind of goes away as we age. And that critical period plasticity, as you know, has been the best studied actually in the visual system.

And the idea that we could reopen that is really fantastic. But for different parts of that eye-brain connection, there's different periods for critical period plasticity. For example, even if you get the amblyopic eye to see well again and then you realign the eyes and now they're working together, a lot of kids will never recover full depth perception, stereopsis, the use of two eyes to see depth, for example.

So why that part of the brain doesn't correct as well as the visual acuity or central vision part of the brain, I'm not sure if we understand that yet.