主题是关于视觉和视力的科学知识以及实用工具。 讲解了眼睛如何工作、视觉如何影响我们的生活，并提供了一系列科学支持的建议，帮助我们保护和增强视力，同时改善心理健康、睡眠和整体表现。
提到“视觉”这个词，人们通常会想到视力，也就是我们辨认形状、物体、面孔和颜色的能力。但实际上，眼睛的功能远不止于此。它们不仅让我们看到世界，还深刻影响我们的情绪、警觉度和生物钟。视觉的起点是我们的眼睛，而眼睛的独特之处在于，它们是唯一暴露在颅骨外的中枢神经系统部分。换句话说，眼睛里的神经视网膜实际上是大脑的一部分，在胚胎发育时被“挤出”颅骨，安置在眼眶中。这使得眼睛成为大脑与外界光线交互的窗口。
眼睛没有所谓的“体外光感知”能力，也就是说，光线信息只能通过眼睛传递到身体的细胞。尽管阳光照在皮肤上感觉很好，但只有通过眼睛，光线才能影响我们的生理和心理状态。眼睛内部有许多关键结构，比如晶状体，它负责将光线聚焦到视网膜上；还有润滑眼睛的泪液，以及睫毛——它们不仅是为了美观，还能触发眨眼反射，保护角膜免受灰尘等异物的侵害。眨眼是人体最快的反射动作。此外，眼睑看似普通，却与脑干的神经回路相连，可以通过特定的视觉行为影响我们的警觉度。
视觉的核心过程始于光线进入眼睛。视网膜上的感光细胞（视杆细胞和视锥细胞）负责将光线转化为电信号。视杆细胞主要在低光环境下工作，比如夜晚，而视锥细胞则负责白天和色彩视觉。这些感光细胞利用维生素A等化学物质，将光转化为电信号，随后通过视网膜神经节细胞传递到大脑。
我们看到的任何物体，比如一个绿苹果，其实并不是直接看到它的颜色或形状，而是大脑根据电信号的模式“猜测”出来的。比如，看到绿色是大脑通过比较绿色光波与其他颜色（如红色和蓝色）的反射差异得出的结论。这种“猜测”非常精准，因为我们通常能准确地抓住杯子或判断物体的距离。
大脑对视觉的处理占据了约40-50%的神经资源，凸显了视觉的重要性。眼睛不仅提供二维图像，还通过两眼间的微小位置差异进行几何和三角计算，创造出深度感。比如，当我们看一个人时，光线落在两只眼睛视网膜上的位置略有不同，大脑利用这种差异计算出对方的距离。这种运算速度极快，令人惊叹。
除了有意识的视觉感知，眼睛还有重要的潜意识功能。休伯曼特别提到一类特殊的视网膜神经节细胞——黑视素细胞。这些细胞对蓝黄光对比度特别敏感，尤其是在清晨或傍晚太阳位于低角度时。这种光线信号通过黑视素细胞传递到大脑的生物钟中枢（位于口腔顶部），从而调节睡眠、情绪、代谢、血糖、多巴胺水平甚至疼痛阈值。换句话说，眼睛的古老功能并不是为了看清物体，而是为了告诉身体和大脑现在是白天还是夜晚。这种时间感知对我们的生物节律至关重要。
基于这些科学原理提出了一系列实用建议。首先，每天早晨花2-10分钟观看自然光，尤其是太阳光（避免直视太阳），可以激活黑视素细胞，设定生物钟，帮助改善睡眠、提升警觉度和稳定情绪。建议尽量不戴太阳镜，以确保光线充分进入眼睛。此外，每天花2小时在户外活动，不仅能让眼睛放松，还能显著降低近视的风险。近视与晶状体的聚焦能力有关，长期盯着近处物体（如手机或电脑）会导致晶状体和相关肌肉过度紧张，增加近视概率。而户外活动让眼睛有机会聚焦远处的地平线，缓解这种压力。
另一个关键建议是锻炼眼睛的“调节”（能力。晶状体通过睫状体的肌肉运动改变形状，以聚焦近处或远处的物体。长时间近距离工作（如看屏幕）会让晶状体变厚，肌肉持续收缩，造成疲劳。休伯曼建议，每专注工作30分钟，就抬头看向远方，放松眼睛和面部肌肉，进入所谓的“全景视觉”，即不聚焦于任何特定物体。这种短暂的放松可以减轻眼睛的压力。如果感到疲倦，可以尝试抬头看向天花板，保持10-15秒，这会激活脑干中与警觉度相关的区域（如蓝斑核），提升清醒感。
推荐练习“平滑追踪”（smooth pursuit），即用眼睛平滑地跟随移动物体，比如观看平滑追踪刺激视频，或者用手指移动一支笔并跟随其轨迹。每次练习2-3分钟，每隔一天进行一次，可以增强眼外肌和大脑视觉追踪系统的协调性。这种练习对保持视力和运动追踪能力非常有益，尤其对那些长时间盯着手机或电脑的人。
为了监测视力，建议在家放置一张斯内伦视力表（Snellen chart），也就是眼科检查中常见的字母表。通过定期测试两眼的视力，可以了解自己的视觉状态。他提醒，视力会因疲劳或时间段而变化，因此最好多次测试取平均值。如果考虑配镜或激光手术，建议找专业的眼科医生或视光师进行检查。
对于儿童的视觉健康，提到双眼视觉的重要性。在7-12岁之前，大脑对两眼的输入差异非常敏感。如果一只眼睛被遮挡或有斜视，可能会导致弱视，甚至永久性视力损伤。因此，儿童需要确保两眼接收均衡的视觉输入。如果发现问题，应尽早咨询神经眼科医生，采取措施如遮盖较强的一只眼睛，迫使较弱的眼睛工作。他还提到，遮盖双眼（如在完全黑暗的洞穴中）会导致视觉系统因缺乏刺激而产生幻觉，这是因为视觉系统急于“猜测”外界信息。
关于营养，澄清一些误解。胡萝卜确实对视力有益，因为富含维生素A，而维生素A是感光细胞功能必需的。但过量摄入维生素A并不会让视力超常，只需达到基本需求即可。深绿色叶菜也富含维生素A，建议以生或轻煮形式食用，以保留营养。还讨论了两种补剂：叶黄素（lutein）和虾青素（astaxanthin）。叶黄素与维生素A代谢相关，有研究表明，对中重度黄斑变性患者有一定保护作用，但对健康眼睛或轻度黄斑变性无明显益处。虾青素是一种红色素，存在于海鲜和火烈鸟羽毛中，能增加眼部血流，可能对眼健康有益，但其效果仍需更多研究。他强调，补剂并非人人必需，应咨询医生后再决定。
健康的心血管系统对视力至关重要。视网膜细胞是人体代谢最活跃的细胞，需要大量血液供应氧气和营养。定期进行耐力运动和力量训练可以改善眼部血流，间接支持视力。还推荐在晚上使用红色镜片眼镜，以过滤屏幕和LED灯的短波长光（蓝光等），从而保护褪黑素分泌，降低皮质醇水平，改善睡眠质量。这些眼镜比普通蓝光阻隔眼镜更有效，因为过滤了更广的短波长光谱。
视力和运动能力是我们自理和照顾他人的核心能力。保护视力看似琐碎，但对生活质量影响巨大。鼓励大家将这些建议融入日常，比如每天看看地平线、练习眼部运动、保持健康饮食和运动习惯。这些简单的行为不仅能增强视力，还能改善整体健康。
Edit:2025.04.25
00:00
Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance.
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- I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford. It is however, part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public. Today's episode is going to be all about vision and eyesight, a topic that's very near and dear to my heart because it's the one that I've been focusing on for well over 25 years of my career.
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When we hear the word vision, we most often think about eyesight or our ability to perceive shapes and objects and faces and colors. However, our eyes are responsible for much more than that, including our mood, our level of alertness, and all of that is included in what we call vision. What is vision? Well, vision starts with the eyes.
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we have no what's called extraocular light perception. While it feels good to have light on our skin, while it feels good to be outside in the sunlight for most people, the only way that light information can get to the cells of your body is through these two little goodies on the front of your face. And for those of you listening, I'm just pointing to my eyes.
01:25
As many of you have heard me say before on this and other podcasts, your eyes in particular, your neural retinas are part of your central nervous system. They are part of your brain. They're the only part of your brain that sits outside the cranial vault. In other words, you have two pieces of your brain that deliberately got squeezed out of the skull during development and placed in these things we call eye sockets. Now the eyes have a lot of other goodies in them that are very important. And those are the goodies that we're going to focus on a lot today.
01:54
There's a lens to focus light precisely to the retina. There are also other pieces of the eye that are designed to keep the eye lubricated. You also have these things that we call eyelashes. Most people don't know this, but eyelashes are there to trigger the blink reflex. They aren't just aesthetically nice. Eyelashes are there so that if a piece of dust or something starts to head towards the cornea, the eye blinks very, very fast. It's the fastest reflex you own.
02:21
We also have these things called eyelids. Now, eyelids might seem like the most boring topic of all, but they are incredibly fascinating. Today, we're going to talk about how you can actually use your visual system to increase your levels of alertness based on the neural circuits that link your brainstem with your eyelids. So let's talk about what the eyes do for vision. Basically, the entire job of the eyes is to collect light information
02:49
and send it off to the rest of the brain in a form that the brain can understand. Remember, no light actually gets in past those neural retinas. It gets to the neural retina and we have specific cells in the eye called photoreceptors. They come in two different types, rods and cones. Cones are mainly responsible for daytime vision and the rods are mainly responsible for vision at night or under low light conditions, generally speaking.
03:19
These photoreceptors, the rods and cones, have chemical reactions inside them that involve things like vitamin A, and that chemical reaction converts the light into electricity. Within the eye, within the retina, there are then a series of stages of processing, and that information eventually gets sent into the brain by a very specific class of neurons. They're called retinal ganglion cells.
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Now, here's what's incredible. I just want you to ponder this for a second. This still blows my mind. Everything you see around you, you're not actually seeing those objects directly. What you're doing is you're making a best guess about what's there based on the pattern of electricity that arrives in your brain. Now, that might just seem totally wild and hard to wrap your head around, but think about it this way, because this is the way it actually works.
04:16
Let's take an example of a color like green or blue. You have cones in your eye that respond best to the wavelength of light that is reflected off, say a green apple. So you don't actually see the green apple. What you see is the light bouncing off that green apple and it goes into your eye
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and you see it and perceive it as round and green, but not because you see anything green. No green light arrives in your brain. What happens is your brain actually compares the amount of green reflection coming off that apple to the amount of red and blue around it.
04:59
What the brain is receiving is a series of signals, electrical signals, and it's comparing electrical signals in order to come up with what we call these perceptions. Like I see something green, a green apple, or I see red. So that's what I'd like you to understand about the way the eye communicates with the brain. I would also like you to understand that the brain itself is making these guesses and that those guesses are largely right. How do I know that?
05:28
Well, they're right because when you reach out to grab a glass, most of the time you grab the glass and you don't miss, right? Most of the time when you make judgments about the world around you based on your visual impression of them, it allows you to move functionally through the world. So the brain is doing these incredible things. It's also creating depth, a sense of depth, even though what arrives from the retina is essentially a readout of a two-dimensional flat image. Your eyes are slightly offset from one another.
05:57
So that for instance, if I look at you, if you were standing right in front of me right now, and I were to look at you, the image of your face, the light bouncing off your face to be more precise, lands on one eye in a slightly different location than it does in the other eye. And then the brain does math. It basically does the equivalent of geometry and trigonometry and essentially figures out how far away you are from me.
06:23
which is just incredible. So the brain does all this very, very fast. And the brain uses about 40 to 50% of its total real estate for vision. That's how important vision is. Now I want to talk about the other aspect of vision, which is the stuff that you don't perceive, the subconscious stuff. And then we'll transition directly into how you can use light and eyesight to control this other stuff, because it's very important. And that other stuff,
06:52
is mood, sleep, and appetite. And there are ways in which you can use these same protocols that I will describe in order to preserve and even enhance your vision, your ability to see things and consciously perceive them. So the protocols we will describe have a lot of carryover to both conscious eyesight and to these subconscious aspects of vision.
07:17
And I just want you to understand a little bit more about the science of seeing, of eyesight and vision, and then all the protocols will make perfect sense. I'd like to take a quick break and acknowledge our sponsor, Eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating, and sleep tracking capacity. Now I've spoken before on this podcast about the critical need for us to get adequate amounts of quality sleep each and every night. Now, one of the best ways to ensure a great night's sleep is to ensure that the temperature of your sleeping environment is correct.
07:45
And that's because in order to fall and stay deeply asleep, your body temperature actually has to drop about one to three degrees. And in order to wake up feeling refreshed and energized, your body temperature actually has to increase by about one to three degrees. Eight Sleep automatically regulates the temperature of your bed throughout the night according to your unique needs. Now I find that extremely useful because I like to make the bed really cool at the beginning of the night
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even colder in the middle of the night and warm as I wake up. That's what gives me the most slow wave sleep and rapid eye movement sleep. And I know that because Eight Sleep has a great sleep tracker that tells me how well I've slept and the types of sleep that I'm getting throughout the night. I've been sleeping on an Eight Sleep mattress cover for four years now, and it has completely transformed and improved the quality of my sleep.
08:28
Their latest model, the Pod 4 Ultra, also has snoring detection that will automatically lift your head a few degrees in order to improve your airflow and stop you from snoring. If you decide to try 8Sleep, you have 30 days to try it at home, and you can return it if you don't like it. No questions asked, but I'm sure that you'll love it.
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Go to eightsleep.com slash Huberman to save up to $350 off your Pod 4 Ultra. Eight Sleep ships to many countries worldwide, including Mexico and the UAE. Again, that's eightsleep.com slash Huberman to save up to $350 off your Pod 4 Ultra. So as amazing as eyesight is, it actually did not evolve for us to see shapes and colors and motion and form. The most ancient cells in our eyes
09:13
And the reason we have eyes is to communicate information about time of day to the rest of the brain and body. Remember, there's no extra ocular photoreception. There's no way for light information to get to all the cells of your body, but every cell in your body needs to know if it's night or day.
09:31
Now, I talked a little bit about this in the episodes on sleep, and this episode is not about sleep, but I want to emphasize that there is a particular category of retinal ganglion cell. Remember the neurons that connect the retina to the brain,
09:47
These are so-called melanopsin retinal ganglion cells named after the opsin that they contain within them. They are essentially photoreceptors. Remember before I said there are photoreceptors and then these ganglion cells? Well, these melanopsin cells, as the name suggests, melanopsin, have their own photoreceptor built inside them. These cells, retinal ganglion cells, communicate to areas of the brain when particular qualities of light are present in your environment.
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and signal to the brain therefore that it's early day or late in the day. They regulate when you'll get sleepy, when you'll feel awake, how fast your metabolism is, excuse me, your blood sugar levels, your dopamine levels, and your pain threshold. These melanopsin ganglion cells have been shown to set the circadian clock and to respond best to the contrast between blue and yellow light of the sort
10:48
that lands on these cells when you view the sun when it's at so-called low solar angle, when it's low in the sky, either in the morning or in the evening. What does all this mean? The most central and important aspect of our biology and perhaps our psychology as well is to anchor
11:08
ourselves in time to know when we exist. We know time at a biological level based on where the sun is. What does this mean for a protocol? It means see, get that light in your eyes early in the day,
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and anytime you want to be awake. So try and get as much sunlight in your eyes during the day as you safely can. You need a lot of this light in order to trigger these melanopsin cells, which would then trigger your circadian clock, which sits above the roof of your mouth, which will signal every cell in your body, including temperature rhythms, et cetera. So first things first, your visual system was not for seeing faces, motion, et cetera. The most ancient cells in your eye
11:49
which are there right now as we speak, are there to inform your body and brain about time of day. So you want to get that bright light early in the day. Absolutely essential, two to 10 minutes. Now, here's another reason to do this. Getting two hours a day of outdoor time without sunglasses has a significant effect on reducing the probability that you will get myopia. Now, myopia or nearsightedness has to do with the way that the lens focuses
12:20
light onto the retina. So remember your eye is an optical device. You have lenses in your eyes and those lenses need to move. It's not a rigid lens like a glass lens, it's a dynamic lens. The eye can dynamically adjust where light lands by moving the lens and changing the shape of the lens in your eye through a process called accommodation. And if you understand this process of accommodation,
12:45
You not only can enhance the health of your eyes in the immediate and long-term, but you also can work better. You'll be able to focus better on physical and mental work. You will be able to concentrate for longer. So much of our mental focus, whether or not it's for cognitive endeavors or physical endeavors, is grounded in where we place our visual focus. What we look at and our ability to hold our concentration there is critically important
13:13
determining how we think. Now, accommodation is our ability to accommodate to things that are up close here or further away. And the way this works is that the iris and the musculature in a structure called the ciliary body move the lens. So when you look far away, okay, when you see things far away, your lens actually moves
13:37
it can flatten out. And you'll notice that it actually is relaxing to look at a horizon. Whereas if I look at something up close to me, like this pen or my phone or a computer screen or this microphone, it takes effort. You'll sense the effort. Now, some of that effort is actually eye movements because you have muscles that can move your eyes within their sockets.
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But a lot of the work quote unquote is neural work of the muscles having to move and contract such that the lens actually gets thicker in order to bring the light to the retina and not to a location in front of it or behind it, so-called accommodation. Now you might say, why are you telling me about accommodation?
14:21
These days, we're spending a lot of time looking at things, mainly our phones up close and computers up close, and we are indoors. In other words, you are not giving your lens the opportunity to flatten out and for these muscles to relieve themselves of this work, but you are also training your eyes to be good at looking at things up close and not far away. And as a consequence, you are reshaping the neural circuitry in your brain, and it is not good
14:52
You want to get outside, not just to lighten the load on your mind or to think about other things, but to maintain the health of your visual system. In other words, you want to exercise these muscles and that involves both
15:09
the lens moving and getting kind of thicker and relaxing that lens. And the relaxation of the lens is actually one of the best things you can do for the musculature of the inner eye. So what's the protocol? You might be surprised, but for every 30 minutes of focused work, you probably want to look up every once in a while and just try and relax your face and eye muscles, including your jaw muscles, because all these things are closely linked in the brainstem.
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and allow your eyes to go into a so-called panoramic vision where you're just not really focusing on anything and then refocus on your work. If you are feeling tired,
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it actually can be beneficial to the wakefulness systems of the brain, including the locus coeruleus and these areas that release norepinephrine to actually look up, to actually look up toward the ceiling. You don't want your chin all the way back, but to look up and to raise your eyes toward the ceiling and to look up and try and hold that for 10 to 15 seconds. It actually triggers some of the areas of the brain that are involved in wakefulness. So if you're somebody who's falling asleep at your work,
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This can be very beneficial. When things are up, we tend to be alert. When everything's focused down, including our eyes, it tends to have a more suppressive or sedative type signaling to the deeper centers of the brain. I'd like to take a quick break and acknowledge our sponsor, AG1.
16:23
AG1 is a vitamin mineral probiotic drink that also contains adaptogens. I started taking AG1 way back in 2012, long before I even knew what a podcast was. I started taking it and I still take it every single day because it ensures that I meet my quota for daily vitamins and minerals and it helps make sure that I get enough prebiotics and probiotics to support my gut health.
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health. Over the past 10 years, gut health has emerged as something that we realize is important not only for the health of our digestion, but also for our immune system and for the production of neurotransmitters and neuromodulators, things like dopamine and serotonin. In other words, gut health is critical for proper brain function. Now, of course, I strive to eat healthy whole foods from unprocessed sources for the majority of my nutritional intake, but
17:05
But there are a number of things in AG1, including specific micronutrients, that are hard or impossible to get from whole foods. So by taking AG1 daily, I get the vitamins and minerals that I need, along with the probiotics and prebiotics for gut health, and in turn, brain and immune system health, and the adaptogens and critical micronutrients that are essential for all organs and tissues of the body.
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So anytime somebody asks me if they were to only take one supplement, what that supplement should be, I always say AG1 because AG1 supports so many different systems in the brain and body that relate to our mental health, physical health, and performance. If you'd like to try AG1, you can go to drinkag1.com slash Huberman. For this month only, April 2025, AG1 is giving away a free one-month supply of omega-3 fish oil along with a bottle of vitamin D3 plus K2.
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As I've highlighted before in this podcast, omega-3 fish oil and vitamin D3 plus K2 have been shown to help with everything from mood and brain health to heart health and healthy hormone production and much more. Again, that's drinkag1.com slash Huberman to get the free one month supply of omega-3 fish oil plus a bottle of vitamin D3 plus K2 with your subscription. How can you improve your vision?
18:17
How can you get better at seeing things? Well, one way is to make sure that you spend at least 10 minutes a day total, at least, viewing things off in the distance. So that would be well over half a mile or more. Try and see a horizon. Try and get your vision out to a location that's beyond the four walls of your house or apartment.
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or the doors of your car and the windshield of your car. I know that can be hard to do, but it's very valuable. So try and see at a distance because it's good for your eyesight. It'll keep this lens nice and elastic and the muscles nice and strong that move the lens. And it has this relaxing component to it. Now, our visual system is exquisitely tuned to motion.
19:01
not just our self-generated motion, but the motion of things around us. And one of the things that it does is something called smooth pursuit. Smooth pursuit is our ability to track individual objects moving as the name suggests smoothly through space in various trajectories. You can actually train or improve your vision
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by looking at smooth pursuit stimuli. And that sounds really boring. Remember the brain follows the eye. It follows the movements of the eye. It has to deal with that. And the neural circuits within the brain have to cope with changes in smooth pursuit. So if you're doing a lot of reading up close, you're not viewing horizons, you're not getting a lot of smooth pursuit type stimulation from your life, or you're just getting it within the confines of a little box on your phone, your vision will get worse. The idea is that
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you want to use the visual system regularly for what it was designed for. And smooth pursuit is a great way to keep the visual and motion tracking systems of the brain and the eye and the extraocular muscles working in a really nice coordinate fashion. So what does this mean? The tool is,
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Spend two to three minutes doing smooth pursuit. There's some programs on YouTube. You can just look up smooth pursuit stimulus. Practice accommodation for a few minutes, maybe every other day. Just bringing something in close. You'll feel the strain of your eyes doing that. Move it out.
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you'll feel a relaxation point. Move it past that relaxation point where you will have to do what's called a virgin's eye movement to maintain focus on that location as it moves out. Bring it back in. Practice that. Practice accommodation and then be sure to give your eyes some rest. Get outside, look at a horizon or do nothing. Just kind of let your eyes go soft. I guess what the yogis would call soft gaze. Practice a little bit of smooth pursuit. You don't have to be neurotic about this, but if you do this often enough,
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meaning every other day, every third day or so, you can be the strange person on the plane or in the classroom doing this, that people might chuckle or look at you funny or tease you, but that's okay because you'll be able to see when they are losing their vision. So you'll get the last laugh. Let's talk about binocular vision and lazy eye. The young brain up until about age seven, but maybe even extending out until about age 12 is extremely lazy.
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to differences in ocular input between the two eyes. My scientific great grandparents won the Nobel prize for discovering so-called critical periods, periods of time in which the brain is more plastic, more able to change. Those two guys, David Heuvel and Torsten Wiesel, thank you, David and Torsten, forever changed the face of visual neuroscience and forever changed the way we think about
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of the young brain. It used to be thought that you wouldn't want to do a surgery on a young kid because of risk of anesthesia in young individuals. But we now know that you need to repair these imbalances that even a few hours of occluding one eye early in life can lead to permanent
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unless something's done. Permanent changes in the way that the brain perceives the outside world such that when that eye is opened up again, the brain actually can't make sense of anything that's coming through it. It shuts down that visual pathway somehow. So what does this all mean in terms of protocols? If you're a young person, do your best to get really good binocular vision, not just at level of your phone or your tablet, but also at distance. You will build strong binocular visual machinery in the brain and at the level of the eyes and the eye musculature.
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Now, if you're somebody who did have an occlusion, what's needed is to cover up the other eye to create an imbalance so that the weak eye, the so-called lazy eye, this is sometimes referred to as amblyopia, that eye has to work harder. Now, you might ask, what happens if you cover both eyes early in life? There are some like retreats and stuff where people go into caves with absolutely no vision.
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creates hallucinations. We'll talk about why that is in just a moment, but here's my suggestion. Try and get balanced visual input through the two eyes. Almost everybody has a dominant eye. It usually doesn't relate to your dominant hand, although it can. And so for me, if I cover up my right eye, I see much less well, much more poorly. It's a little bit fuzzy and I have to work harder in order to see the camera, for instance, than if I cover up my left eye. And if you do have strong imbalances between the two eyes,
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which can be caused by
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and lens issues can be caused by neuromuscular issues, et cetera, to try and get those dealt with as early as possible by contacting a really good ophthalmologist and ideally a neuro-ophthalmologist. It's very common for young children, babies to have an eye with strabismus that either deviates out or that deviates in. It is important to correct that if you would like to have balanced vision between the two eyes and for the brain to respond
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equally to the two eyes and to have, I would say high fidelity quality vision. Hallucinations are a property of the visual system. And it was always thought that hallucinations arise because of over activation or activation of certain aspects of the visual system. I just briefly want to mention a paper that was published by my good friend and phenomenal scientist and physicist for that matter, Chris Neil, who's up at the University of Oregon in Eugene, they studied LSD like compounds and discovered
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that hallucinations actually occur because
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portions of your brain become underactive. The visual portions of your brain are under stimulated. This is probably why when people go into these cave retreats, something I've never done, I don't think I ever will do where it's completely black, pretty soon they start hallucinating. They start seeing things even though there's nothing there. The visual system is desperate to make guesses about what's out in the world. It's like the eager beaver of your brain. It's like, what's out there? What's out there? What's out there?
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it turns out that hallucinations are an under activation of the visual system and then a compensatory, a compensation by which the visual system creates activity and hallucinations. So if you're in the dark long enough, you start to hallucinate and see things. So that's a little note about hallucinations.
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I'd like to take a quick break and thank one of our sponsors, Roka. Roka makes eyeglasses and sunglasses that are the absolute highest quality. I've been wearing Roka readers and sunglasses for years now, and I absolutely love them. They're lightweight, they have superb optics, and they have lots of frames to choose from. Roka and I recently teamed up to create a new pair of red lens glasses.
25:29
These Red Lens glasses are meant to be worn in the evening after the sun goes down. They filter out short wavelength light that comes from screens and from LED lights, which are the most common indoor lighting nowadays. I want to emphasize Roka Red Lens glasses are not traditional blue blockers.
25:44
They do filter out blue light, but they filter out a lot more than just blue light. In fact, they filter out the full range of short wavelength light that suppresses the hormone melatonin. By the way, you want melatonin high in the evening and at night, makes it easy to fall and stay asleep. And those short wavelengths trigger increases in cortisol.
26:01
Increases in cortisol are great in the early part of the day, but you do not want increases in cortisol in the evening and at night. These Roka Red Lens glasses ensure normal, healthy increases in melatonin and that your cortisol levels stay low, which is again, what you want in the evening and at night.
26:17
In doing so, these Roka Red Lens glasses really help you calm down and improve your transition to sleep. Roka Red Lens glasses also look great. They have a ton of different frames to select from, and you can wear them out to dinner or concerts, and you can still see things. I don't recommend you wear them while driving just for safety purposes, but if you're out to dinner, you're at a concert, you're at a friend's house, or you're just at home, pop those Roka Red Lens glasses on, and you'll really notice the difference in terms of your levels of calm and all the sleep stuff I mentioned earlier.
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If you'd like to try ROKA, go to roka.com, that's R-O-K-A.com and enter the code Huberman to save 20% off your first order. Again, that's roka.com and enter the code Huberman at checkout. One of the things that you can do to improve your vision, and it's also kind of fun, is to put a Snellen chart in your home. A Snellen chart is that list of letters. If you go to the dreaded Department of Motor Vehicles, have you cover up an eye, read the letters on the chart,
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The letters of course get smaller and smaller. They're trying to figure out roughly what your vision is. Cover up the other eye. You'll do that. This is something that's not often mentioned, but your performance on the Snellen chart will vary depending on time of day, because your level of fatigue and your ability to control that accommodation and other mechanisms of the eye muscles will vary. So you can take it as an average. It's,
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It's also a good thing if you're going to get your vision tested for corrective lenses or maybe you're going to do laser surgery or something of that sort, if you're thinking about any of that, to really get it measured by a professional. Get your vision tested by somebody who really understands vision, like an ophthalmologist or a really good optometrist. If you put a Snellen chart in your home, you can do that as part of your visual training. Now, this might seem excessively nerdy,
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what is more important than your eyesight, right? Eyesight is so vital. It's right up there with movement and our ability to move, to generate, to get up out of chairs and to walk and to run and to take care of ourselves. Eyesight and movement are the main ways that we are able to take care of ourselves and take care of others. When you start having compromised eyesight or compromised movement, people need to take care of us and we become much more challenged in moving through our daily life. So while it might seem nerdy to have a Snellen chart in your home,
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or to do a smooth pursuit exercise a couple of times a week, or to get outside for a few hours a day and do your reading or your laptop work there. Preserving your eyesight and preserving your vision is one of the most life enhancing or quality of life enhancing things that you can do. Now, of course, there are genetic factors and there are injury related factors that can compromise eyesight and our ability to see. And of course,
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the things I'm talking about today aren't going to solve all those issues, but they can have a tremendous positive impact if you're willing to do just a little bit of work. So I do want to talk about a few other things that can perhaps improve vision. I want to dispel a few myths about stuff to take to improve vision. So now you understand a lot about the biology of vision. You understand that light has to arrive at the retina and get converted into electrical signals.
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That process requires things like vitamin A, a fat soluble vitamin. It requires things like the carotenoids. That metabolic cascade, that biochemical cascade is essential for vision. And this is why you've been told that carrots help you see better because they're high in vitamin A. There are a few simple things you can do to support your vision. First of all, it is true that carrots
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Eating vegetables, the dark leafy vegetables and things like carrots that have vitamin A in abundance and eating them in close to their raw form. So naturally occurring foods that contain a lot of vitamin A in their raw form can help support vision. Now, does that mean that if you ingest super physiological amounts of that stuff that it's going to make your vision that much better? No, but you do need a threshold level of vitamin A in order to see.
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and in order to see well. Now, there's a lot of excitement nowadays about supplementation to help support the health of the visual system. But I want to talk about
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a molecule that's in a lot of supplements to support vision. And there are some really good data on, and that's lutein. What is this lutein stuff? Well, lutein is in the pathway that relates to vitamin A and the formation of the opsin, the photopigment that captures light in the back of your eye, literally absorbs light pigment in your eye.
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and converts that into electrical signals and allows you to see. And there is some evidence, I spoke to our chair of ophthalmology, there is some evidence through quality peer reviewed studies that supplementing with lutein can help offset some of the detrimental effects of age-related macular degeneration. But I want to emphasize, but, or emphasize however,
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only for individuals with moderate to severe macular degeneration. For people that have normal vision or with just a low degree of macular degeneration, these studies did not see a significant improvement of vision from supplementing with lutein.
31:39
And the other one is A-S-T-A-X-A-N-T-H-I-N. What is Aztec Saxton? It's a really interesting compound. It's the red pink pigment found in various seafoods. I'm not a big seafood fan, but like certain fish, like you'll see at the fish market will have that red pink pigment. And it's also in the feathers of flamingos. It's structurally similar to beta carotene. So it's very pro vitamin A.
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but it has some chemical differences which may make it safer than vitamin A. Remember, vitamin A is a lipid-soluble vitamin, so it can be stored in our body for long periods of time. What is the deal with this astaxanthin? You know, what are its drawbacks? Well, it has a number of different effects, but the most notable for sake of this episode is the one on ocular blood flow. It does seem to increase the amount of ocular blood flow, so the blood supply to the eyes. So that makes it an interesting compound.
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It's also been shown to have positive effects on things like skin elasticity, skin moisture, skin quality, et cetera, probably due to its effects on blood flow. So lutein, astaxan, A-S-T-A-X-A-N-T-H-I-N. So everything I've talked about today relates to studies that were done and published in quality peer-reviewed journals. That doesn't necessarily mean you want to run out and start taking this stuff,
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“that I've described or even doing the protocols “I've described, I've given you an array, a palette, “a buffet, if you will, of things that you could do “to try and enhance or support your vision “depending on how good your vision is, “your family history of vision and vision loss, “your occupational hazards. “People that work with metal filings “that are flying out of machines “are going to have a higher degree of vision,
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you know, risk to their visual system than will people who just do office work. Although if you're doing a lot of office work, chances are you're not getting a lot of long view vision. Your accommodation mechanisms are going to start to suffer over time. I think we can reliably predict that. So I've tried to give you an array of behavioral tools
33:39
And we did touch upon some supplementation tools. I'd be remiss if I didn't say that because blood flow is so critical for the neurons of the eye, remember these are the most metabolically active cells in your entire body, the cells within your retina, because blood flow is required to get them the energy and nutrients they need. Having a healthy cardiovascular system
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doing endurance work, doing strength training work regularly is going to support your eyes and your brain and your vision. It's indirect, but it's essential, right? It's necessary, but it's not going to be sufficient. You're going to have to do other things to support your eyesight as well. But having a healthy cardiovascular system, because it's going to deliver blood and oxygen and nutrients to this incredible apparatus on the front of your face,
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these two pieces of brain is going to support your overall brain health and vision over time. Last but not least, I want to thank you for your time and attention today, your willingness to learn about vision and the visual system and the various things that you can do to help support the health and functioning of your visual system. And of course, I want to thank you for your interest in science.
Edit:2025.04.25
