Tool for Better Eyesight & Eye Health | Dr. Jeff Goldberg & Dr. Andrew Huberman
00:00:00.000 | - What can we say about the environmental conditions
00:00:05.000 | in which kids are seen from the time they're born
00:00:10.880 | through let's say adolescence and their teen years
00:00:13.400 | in terms of how their visual system wires up?
00:00:16.760 | And are there any recommendations
00:00:19.120 | that are coming from the scientific literature,
00:00:22.300 | clinical studies, clinical trials, excuse me, or otherwise
00:00:25.600 | that indicate what a healthy visual environment consists of?
00:00:30.600 | - Yeah, yeah.
00:00:32.040 | That's a great question.
00:00:33.080 | And actually it's really relevant these days
00:00:36.600 | because myopia is so common.
00:00:40.480 | It's more common in Asian populations.
00:00:47.020 | It's called an epidemic in China.
00:00:50.620 | In California, we have a lot of Asian heritage
00:00:53.660 | or Asian Americans.
00:00:54.920 | And so we see a lot, like at Stanford,
00:00:56.980 | we see a lot of myopia in kids and adults
00:01:01.980 | and really starting to get thoughtful
00:01:04.640 | on the science of myopia control.
00:01:06.840 | How do we provide the right environments?
00:01:09.660 | Now, what's interesting is that for decades,
00:01:12.380 | the assumption, some of the data really led us
00:01:17.100 | to the path of thinking like, gosh,
00:01:18.860 | the more you spend at near activities,
00:01:21.600 | and these are mouse model experiments like you described,
00:01:24.200 | but also well-designed human cohort studies,
00:01:27.760 | figuring out like asking kids and families,
00:01:30.760 | like how long is your kid reading
00:01:32.320 | or in front of the computer?
00:01:33.740 | How myopic are they?
00:01:34.900 | How nearsighted are they?
00:01:36.460 | Versus how much time is your kid in front of the computer
00:01:40.000 | doing near work?
00:01:41.200 | How myopic or nearsighted are they?
00:01:43.220 | And these well-designed cohort studies
00:01:45.040 | did point towards this concept
00:01:48.100 | that if you do too much near work as a kid,
00:01:51.480 | that you're more likely to develop nearsightedness
00:01:55.200 | as you get through those sort of preteen
00:01:58.760 | and even into the teen years,
00:02:00.320 | which is when most of that myopia progression
00:02:02.820 | or eyeball elongation is actually happening
00:02:05.740 | to cause nearsightedness.
00:02:08.040 | It's only been in the last few years
00:02:10.280 | that some really exciting studies
00:02:11.800 | have actually pointed in a slightly different direction.
00:02:14.820 | And that's that maybe it's not all,
00:02:18.360 | not to say it's not about near activity,
00:02:20.720 | but maybe it's not all about near activity.
00:02:22.600 | Maybe it's actually a little more
00:02:24.080 | about the kind of light we're getting into our eyes.
00:02:27.800 | And I think you've talked about this before,
00:02:29.560 | and it's really important.
00:02:31.120 | When they've now studied and asked the kids,
00:02:32.960 | instead of just how much near
00:02:34.240 | and how much far are you doing,
00:02:36.040 | how much time are you spending indoors in indoor lighting,
00:02:38.860 | which doesn't have full spectrum light
00:02:40.560 | in a typical indoor environment,
00:02:42.340 | versus how much time are you spending outdoors,
00:02:45.120 | playing in the yard?
00:02:46.360 | You could be reading outside,
00:02:47.680 | but what kind of time are you spending outside?
00:02:51.500 | And of course, when you're outside in sunlight,
00:02:54.800 | even it's in direct sunlight,
00:02:56.220 | you're getting a different spectrum
00:02:57.880 | of kind of full spectrum lighting from the sun.
00:03:00.800 | And it looks like it's pretty clear now, actually,
00:03:03.640 | that it has maybe more to do with outdoor lighting time
00:03:08.640 | than just near work.
00:03:11.240 | And so I think that we've actually already seen
00:03:15.720 | the first couple of randomized controlled trials
00:03:19.640 | where they're having kids intentionally
00:03:22.040 | spending time outdoors versus sort of standard life,
00:03:25.400 | which is gonna be often much more indoor time.
00:03:29.080 | And seeing some effects,
00:03:30.880 | you follow those kids over a couple of years,
00:03:33.720 | and the kids who spend time outdoors
00:03:36.800 | are progressing in their nearsightedness less.
00:03:40.060 | Like their nearsighted prescription is not getting as strong
00:03:44.560 | as the kids who are spending more time indoors.
00:03:46.840 | And there's some pretty good biology
00:03:48.760 | that's getting worked out, going back to animal models,
00:03:51.160 | more about how that might be working in the retina,
00:03:54.800 | in this inside the eye.
00:03:56.720 | But it's pretty compelling concept.
00:03:59.480 | And so, as a parent, you may wanna be telling your kid,
00:04:04.440 | like, okay, yeah, I want you to read that book,
00:04:07.200 | or if your kid's playing on the phone or something like that
00:04:10.760 | or the iPad or something like that,
00:04:12.360 | they're allowed that time.
00:04:13.920 | Okay, you can have that time,
00:04:15.200 | but I want you to spend some of the time
00:04:16.760 | that you're doing that outdoors.
00:04:18.480 | - Are there any thresholds for the amount of time
00:04:20.520 | that one would suggest their child be outdoors
00:04:24.240 | to get that full spectrum light?
00:04:25.760 | - It's a great question.
00:04:27.080 | We talk about cohort studies
00:04:29.600 | where we just ask people, what are they doing?
00:04:32.480 | And there seems to be a little bit
00:04:34.020 | of what we would call a dose-dependent response.
00:04:36.280 | Maybe the more time outdoors might be better.
00:04:38.680 | We don't know if there's an upper limit.
00:04:40.120 | Like, gosh, if you go over two or three hours,
00:04:42.160 | there's no additional benefit.
00:04:44.240 | We talk about that in cohort studies.
00:04:46.000 | The real gold standard
00:04:47.480 | for answering these kinds of questions
00:04:50.280 | are randomized controlled trials
00:04:53.080 | and specifically placebo-controlled
00:04:55.120 | or a control group that's not getting the intervention.
00:04:58.520 | That's our highest level of evidence for clinical evidence
00:05:01.920 | for any of this kind of science
00:05:04.000 | when we're talking about humans
00:05:05.280 | or preclinical models in the laboratory.
00:05:07.920 | And the study that hasn't been done yet
00:05:10.900 | to really answer that question
00:05:12.840 | is to randomize kids to telling this group of kids,
00:05:16.640 | you just do your normal life.
00:05:18.440 | Tell this group of kids, we want you outside an hour.
00:05:21.280 | This group of kids, we want you outside two hours a day.
00:05:24.180 | This group of kids, three hours a day.
00:05:26.120 | And see between the groups, is there a big difference?
00:05:29.400 | Like, we have pretty good evidence now
00:05:31.240 | from the studies that have been done
00:05:32.760 | that the difference between zero
00:05:34.760 | and one or two hours is clearly there.
00:05:38.760 | Is five minutes enough?
00:05:40.320 | Is five hours better?
00:05:41.880 | I don't think we know the answers to those questions yet.
00:05:44.280 | Like, what's the right dose?
00:05:46.520 | But there's probably at least some dose dependence to that.
00:05:50.280 | - And I can imagine it's a little bit hard to tease apart
00:05:52.960 | the near far viewing from the indoor outdoor
00:05:55.520 | because yes, of course,
00:05:57.120 | a child could be outside on an iPad up close,
00:06:00.980 | but it's hard to imagine that at some point
00:06:02.720 | they aren't seeing off into the distance,
00:06:04.400 | far viewing as it's called.
00:06:07.020 | And the reverse is also true if you're indoors,
00:06:09.360 | unless you live in a very, very large home
00:06:11.560 | or you're staring off a balcony,
00:06:13.740 | far viewing is much harder to achieve.
00:06:15.940 | And perhaps it isn't important to isolate these variables.
00:06:20.240 | Although I can see the challenge
00:06:21.400 | in developing a really good clinical trial,
00:06:23.520 | randomized clinical trial for this.
00:06:25.320 | Meanwhile, I'll go into the grave shouting,
00:06:30.060 | or saying rather and suggesting
00:06:31.920 | that people get some morning sunlight in their eyes
00:06:33.640 | to set their circadian rhythm.
00:06:36.140 | But far viewing a few, at least a few minutes
00:06:39.540 | and ideally hours per day,
00:06:41.580 | or a mixture of near and far viewing by being outdoors
00:06:43.980 | just seems like a good thing to do regardless of age.
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