[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.89,0:00:02.85,Default,,0000,0000,0000,,Every single one of us will lose
Dialogue: 0,0:00:02.85,0:00:06.01,Default,,0000,0000,0000,,or has already lost something\Nwe rely on every single day.
Dialogue: 0,0:00:06.72,0:00:09.22,Default,,0000,0000,0000,,I am of course talking about our keys.
Dialogue: 0,0:00:09.53,0:00:10.93,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:00:11.19,0:00:12.21,Default,,0000,0000,0000,,Just kidding.
Dialogue: 0,0:00:12.21,0:00:15.54,Default,,0000,0000,0000,,What I actually want to talk about\Nis one of our most important senses:
Dialogue: 0,0:00:15.54,0:00:16.54,Default,,0000,0000,0000,,vision.
Dialogue: 0,0:00:16.54,0:00:19.26,Default,,0000,0000,0000,,Every single day we each lose\Na little bit of our ability
Dialogue: 0,0:00:19.26,0:00:20.59,Default,,0000,0000,0000,,to refocus our eyes
Dialogue: 0,0:00:20.59,0:00:22.33,Default,,0000,0000,0000,,until we can't refocus at all.
Dialogue: 0,0:00:22.84,0:00:24.96,Default,,0000,0000,0000,,We call this condition presbyopia,
Dialogue: 0,0:00:24.96,0:00:27.32,Default,,0000,0000,0000,,and it affects two billion\Npeople worldwide.
Dialogue: 0,0:00:27.55,0:00:29.32,Default,,0000,0000,0000,,That's right, I said billion.
Dialogue: 0,0:00:29.52,0:00:31.20,Default,,0000,0000,0000,,If you haven't heard of presbyopia,
Dialogue: 0,0:00:31.20,0:00:34.01,Default,,0000,0000,0000,,and you're wondering, \N"Where are these two billion people?"
Dialogue: 0,0:00:34.01,0:00:36.07,Default,,0000,0000,0000,,here's a hint before\NI get into the details.
Dialogue: 0,0:00:36.07,0:00:39.22,Default,,0000,0000,0000,,It's the reason why people wear\Nreading glasses or bifocal lenses.
Dialogue: 0,0:00:39.54,0:00:42.44,Default,,0000,0000,0000,,I'll get started by describing\Nthe loss in refocusing ability
Dialogue: 0,0:00:42.44,0:00:43.77,Default,,0000,0000,0000,,leading up to presbyopia.
Dialogue: 0,0:00:43.95,0:00:44.97,Default,,0000,0000,0000,,As a newborn,
Dialogue: 0,0:00:44.97,0:00:48.42,Default,,0000,0000,0000,,you would have been able to focus\Nas lose as six-and-a-half centimenters
Dialogue: 0,0:00:48.42,0:00:49.64,Default,,0000,0000,0000,,if you wish to.
Dialogue: 0,0:00:49.64,0:00:52.70,Default,,0000,0000,0000,,By your mid-20s, you have about\Nhalf of that focusing power left.
Dialogue: 0,0:00:52.73,0:00:53.95,Default,,0000,0000,0000,,10 centimeters or so,
Dialogue: 0,0:00:53.95,0:00:56.48,Default,,0000,0000,0000,,but close enough that you never\Nnotice the difference.
Dialogue: 0,0:00:56.48,0:00:57.64,Default,,0000,0000,0000,,By your late-40s though,
Dialogue: 0,0:00:57.64,0:01:00.01,Default,,0000,0000,0000,,the closest you can focus\Nis about 25 centimeters,
Dialogue: 0,0:01:00.01,0:01:01.24,Default,,0000,0000,0000,,maybe even farther.
Dialogue: 0,0:01:01.24,0:01:03.32,Default,,0000,0000,0000,,Losses in focusing ability\Nbeyond this point
Dialogue: 0,0:01:03.32,0:01:05.53,Default,,0000,0000,0000,,start effecting near-vision\Ntasks like reading,
Dialogue: 0,0:01:05.53,0:01:07.49,Default,,0000,0000,0000,,and by the time you reach age 60,
Dialogue: 0,0:01:07.49,0:01:09.99,Default,,0000,0000,0000,,nothing within a meter\Nradius of you is clear.
Dialogue: 0,0:01:10.17,0:01:12.34,Default,,0000,0000,0000,,Right now some of you\Nare probably thinking,
Dialogue: 0,0:01:12.34,0:01:15.68,Default,,0000,0000,0000,,that sounds bad but he means\Nyou in a figurative sense,
Dialogue: 0,0:01:15.68,0:01:18.62,Default,,0000,0000,0000,,only for the people that actually\Nend up with presbyopia.
Dialogue: 0,0:01:19.13,0:01:23.58,Default,,0000,0000,0000,,But no, when I say you, I literally mean\Nthat every single one of you
Dialogue: 0,0:01:23.58,0:01:26.43,Default,,0000,0000,0000,,will someday be presbyopic\Nif you aren't already.
Dialogue: 0,0:01:26.85,0:01:28.24,Default,,0000,0000,0000,,That sounds a bit troubling.
Dialogue: 0,0:01:28.24,0:01:31.90,Default,,0000,0000,0000,,I want to remind you that presbyopia\Nhas been with us for all of human history
Dialogue: 0,0:01:31.90,0:01:34.72,Default,,0000,0000,0000,,and we've done a lot of different\Nthings to try and fix it.
Dialogue: 0,0:01:34.73,0:01:38.46,Default,,0000,0000,0000,,So to start, let's imagine\Nthat you're sitting at a desk, reading.
Dialogue: 0,0:01:38.70,0:01:40.09,Default,,0000,0000,0000,,If you were presbyopic,
Dialogue: 0,0:01:40.09,0:01:42.10,Default,,0000,0000,0000,,it might look a little\Nsomething like this.
Dialogue: 0,0:01:42.10,0:01:44.84,Default,,0000,0000,0000,,Anything close by,\Nlike the magazine, will be blurry.
Dialogue: 0,0:01:45.20,0:01:46.45,Default,,0000,0000,0000,,Moving on to solutions.
Dialogue: 0,0:01:46.45,0:01:48.04,Default,,0000,0000,0000,,First, reading glasses.
Dialogue: 0,0:01:48.28,0:01:50.32,Default,,0000,0000,0000,,These have lenses\Nwith a single focal power
Dialogue: 0,0:01:50.33,0:01:52.41,Default,,0000,0000,0000,,tuned so that near objects\Ncome into focus.
Dialogue: 0,0:01:52.61,0:01:55.32,Default,,0000,0000,0000,,But far objects necessarily\Ngo out of focus,
Dialogue: 0,0:01:55.32,0:01:57.76,Default,,0000,0000,0000,,meaning you have to constantly\Nswitch back and forth
Dialogue: 0,0:01:57.76,0:01:59.54,Default,,0000,0000,0000,,between wearing and not wearing them.
Dialogue: 0,0:01:59.54,0:02:00.76,Default,,0000,0000,0000,,To solve this problem
Dialogue: 0,0:02:00.76,0:02:04.03,Default,,0000,0000,0000,,Benjamin Franklin invented\Nwhat he called "double spectacles."
Dialogue: 0,0:02:04.24,0:02:06.25,Default,,0000,0000,0000,,Today we call those bifocals,
Dialogue: 0,0:02:06.25,0:02:09.84,Default,,0000,0000,0000,,and what they let him do\Nwas see far when he looked up
Dialogue: 0,0:02:09.84,0:02:11.46,Default,,0000,0000,0000,,and see near when he looked down.
Dialogue: 0,0:02:11.46,0:02:14.46,Default,,0000,0000,0000,,Today we also have progressive lenses\Nwhich get rid of the line
Dialogue: 0,0:02:14.46,0:02:17.03,Default,,0000,0000,0000,,by smoothly varying the focal power\Nfrom top to bottom.
Dialogue: 0,0:02:17.03,0:02:18.44,Default,,0000,0000,0000,,The downside to both of these
Dialogue: 0,0:02:18.44,0:02:21.24,Default,,0000,0000,0000,,is that you lose field of vision\Nat any given distance
Dialogue: 0,0:02:21.24,0:02:23.81,Default,,0000,0000,0000,,because it gets split up\Nfrom top to bottom like this.
Dialogue: 0,0:02:23.81,0:02:25.18,Default,,0000,0000,0000,,To see why that's a problem,
Dialogue: 0,0:02:25.18,0:02:27.98,Default,,0000,0000,0000,,imagine that you're climbing\Ndown a ladder or stairs.
Dialogue: 0,0:02:28.17,0:02:31.32,Default,,0000,0000,0000,,You look down to get\Nyour footing but it's blurry.
Dialogue: 0,0:02:31.69,0:02:33.08,Default,,0000,0000,0000,,Why would it be blurry?
Dialogue: 0,0:02:33.30,0:02:36.57,Default,,0000,0000,0000,,Well, you look down\Nand that's the near part of the lens,
Dialogue: 0,0:02:36.57,0:02:39.28,Default,,0000,0000,0000,,but the next step was past arm's reach,
Dialogue: 0,0:02:39.28,0:02:41.10,Default,,0000,0000,0000,,which for your eyes, counts as far.
Dialogue: 0,0:02:41.27,0:02:44.14,Default,,0000,0000,0000,,The next solution I want to point out\Nis a little less common
Dialogue: 0,0:02:44.14,0:02:46.76,Default,,0000,0000,0000,,but comes up a lot in contact lenses\Nor LASIK surgeries,
Dialogue: 0,0:02:46.76,0:02:48.07,Default,,0000,0000,0000,,and it's called monovision.
Dialogue: 0,0:02:48.07,0:02:50.59,Default,,0000,0000,0000,,It works by setting up\Nthe dominant eye to focus far
Dialogue: 0,0:02:50.59,0:02:52.11,Default,,0000,0000,0000,,and the other eye to focus near.
Dialogue: 0,0:02:52.11,0:02:54.83,Default,,0000,0000,0000,,Your brain does the work\Nof intelligently putting together
Dialogue: 0,0:02:54.83,0:02:56.82,Default,,0000,0000,0000,,the sharpest parts from each eye's view,
Dialogue: 0,0:02:56.82,0:02:59.00,Default,,0000,0000,0000,,but the two eyes see\Nslightly different things,
Dialogue: 0,0:02:59.00,0:03:01.62,Default,,0000,0000,0000,,and that makes it harder\Nto judge distances binocularly.
Dialogue: 0,0:03:01.62,0:03:03.15,Default,,0000,0000,0000,,So where does that all leave us?
Dialogue: 0,0:03:03.15,0:03:06.00,Default,,0000,0000,0000,,It seems like we've come up\Nwith a lot of different solutions
Dialogue: 0,0:03:06.00,0:03:08.34,Default,,0000,0000,0000,,but none of them quite restore\Nnatural refocusing.
Dialogue: 0,0:03:08.34,0:03:10.33,Default,,0000,0000,0000,,None of them let you\Njust look at something
Dialogue: 0,0:03:10.33,0:03:11.74,Default,,0000,0000,0000,,and expect it to be in focus.
Dialogue: 0,0:03:11.74,0:03:12.74,Default,,0000,0000,0000,,But why?
Dialogue: 0,0:03:12.84,0:03:13.98,Default,,0000,0000,0000,,Well, to explain that
Dialogue: 0,0:03:13.98,0:03:16.69,Default,,0000,0000,0000,,we'll want to take a look\Nat the anatomy of the human eye.
Dialogue: 0,0:03:16.69,0:03:19.88,Default,,0000,0000,0000,,The part of the eye that allows us\Nto refocus to different distances
Dialogue: 0,0:03:19.88,0:03:21.40,Default,,0000,0000,0000,,is called the crystalline lens.
Dialogue: 0,0:03:21.65,0:03:25.64,Default,,0000,0000,0000,,There are muscles surrounding the lens\Nthat can deform it into different shapes,
Dialogue: 0,0:03:25.64,0:03:27.79,Default,,0000,0000,0000,,which in turn changes its focusing power.
Dialogue: 0,0:03:27.79,0:03:29.91,Default,,0000,0000,0000,,What happens when someone\Nbecomes presbyopic?
Dialogue: 0,0:03:30.21,0:03:32.40,Default,,0000,0000,0000,,It turns out that\Nthe crystalline lens stiffens
Dialogue: 0,0:03:32.40,0:03:35.08,Default,,0000,0000,0000,,to the point that it doesn't\Nreally change shape anymore.
Dialogue: 0,0:03:35.08,0:03:39.08,Default,,0000,0000,0000,,Now, thinking back\Non all the solutions I listed earlier,
Dialogue: 0,0:03:39.08,0:03:42.69,Default,,0000,0000,0000,,we can see that they all have\Nsomething in common with the others
Dialogue: 0,0:03:42.69,0:03:44.31,Default,,0000,0000,0000,,but not with our eyes,
Dialogue: 0,0:03:44.31,0:03:46.20,Default,,0000,0000,0000,,and that is that they're all static.
Dialogue: 0,0:03:46.29,0:03:49.09,Default,,0000,0000,0000,,It's like the optical equivalent\Nof a pirate with a peg leg.
Dialogue: 0,0:03:49.09,0:03:51.99,Default,,0000,0000,0000,,What is the optical equivalent\Nof a modern prosthetic leg?
Dialogue: 0,0:03:52.29,0:03:55.52,Default,,0000,0000,0000,,The last several decades have seen\Nthe creation and rapid development
Dialogue: 0,0:03:55.52,0:03:57.93,Default,,0000,0000,0000,,of what are called "focus-tunable lenses."
Dialogue: 0,0:03:58.33,0:04:00.02,Default,,0000,0000,0000,,There are several different types.
Dialogue: 0,0:04:00.02,0:04:01.81,Default,,0000,0000,0000,,Mechanically-shifted Alvarez lenses,
Dialogue: 0,0:04:01.81,0:04:03.45,Default,,0000,0000,0000,,deformable liquid lenses
Dialogue: 0,0:04:03.45,0:04:05.88,Default,,0000,0000,0000,,and electronically-switched, \Nliquid crystal lenses.
Dialogue: 0,0:04:05.96,0:04:07.69,Default,,0000,0000,0000,,Now these have their own trade-offs,
Dialogue: 0,0:04:07.69,0:04:10.29,Default,,0000,0000,0000,,but what they don't skimp on\Nis the visual experience.
Dialogue: 0,0:04:10.29,0:04:13.62,Default,,0000,0000,0000,,Full, field-of-view vision that can be\Nsharp at any desirable distance.
Dialogue: 0,0:04:13.62,0:04:14.62,Default,,0000,0000,0000,,OK, great.
Dialogue: 0,0:04:14.62,0:04:16.19,Default,,0000,0000,0000,,The lenses we need already exist.
Dialogue: 0,0:04:16.19,0:04:17.29,Default,,0000,0000,0000,,Problem solved, right?
Dialogue: 0,0:04:17.79,0:04:19.00,Default,,0000,0000,0000,,Not so fast.
Dialogue: 0,0:04:19.16,0:04:22.05,Default,,0000,0000,0000,,Focus-tunable lenses add a bit\Nof complexity to the equation.
Dialogue: 0,0:04:22.16,0:04:25.98,Default,,0000,0000,0000,,The lenses don't have any way of knowing\Nwhat distance they should be focused to.
Dialogue: 0,0:04:25.98,0:04:28.89,Default,,0000,0000,0000,,What we really need are glasses\Nthat, when you're looking far,
Dialogue: 0,0:04:28.89,0:04:30.00,Default,,0000,0000,0000,,far objects are sharp,
Dialogue: 0,0:04:30.00,0:04:31.15,Default,,0000,0000,0000,,and when you look near,
Dialogue: 0,0:04:31.15,0:04:33.92,Default,,0000,0000,0000,,near objects come into focus\Nanywhere in your field of view
Dialogue: 0,0:04:33.92,0:04:35.91,Default,,0000,0000,0000,,and without you having to think about it.
Dialogue: 0,0:04:35.91,0:04:38.38,Default,,0000,0000,0000,,What I've worked on\Nthese last few years at Stanford
Dialogue: 0,0:04:38.38,0:04:40.91,Default,,0000,0000,0000,,is building that exact intelligence\Naround the lenses.
Dialogue: 0,0:04:40.91,0:04:44.48,Default,,0000,0000,0000,,Our prototype borrows technology\Nfrom virtual and augmented reality systems
Dialogue: 0,0:04:44.48,0:04:45.92,Default,,0000,0000,0000,,to estimate focusing distance.
Dialogue: 0,0:04:45.92,0:04:49.49,Default,,0000,0000,0000,,We have an eye tracker that can tell\Nwhat direction our eyes are focused in.
Dialogue: 0,0:04:49.49,0:04:50.49,Default,,0000,0000,0000,,Using two of these,
Dialogue: 0,0:04:50.49,0:04:52.69,Default,,0000,0000,0000,,we can directly triangulate\Nyour gaze direction
Dialogue: 0,0:04:52.69,0:04:53.86,Default,,0000,0000,0000,,to get a focus estimate.
Dialogue: 0,0:04:53.86,0:04:54.86,Default,,0000,0000,0000,,Just in case though,
Dialogue: 0,0:04:54.86,0:04:57.48,Default,,0000,0000,0000,,to increase reliability\Nwe also added a distance sensor.
Dialogue: 0,0:04:57.48,0:04:59.82,Default,,0000,0000,0000,,The sensor is a camera\Nthat looks out at the world
Dialogue: 0,0:04:59.82,0:05:01.42,Default,,0000,0000,0000,,and reports distances to objects.
Dialogue: 0,0:05:01.42,0:05:04.42,Default,,0000,0000,0000,,We can again use your gaze direction\Nto get a distance estimate
Dialogue: 0,0:05:04.42,0:05:05.60,Default,,0000,0000,0000,,for a second time.
Dialogue: 0,0:05:05.60,0:05:07.58,Default,,0000,0000,0000,,We then fuse those two distance estimates
Dialogue: 0,0:05:07.58,0:05:10.08,Default,,0000,0000,0000,,and update the focus-tunable\Nlens power accordingly.
Dialogue: 0,0:05:10.27,0:05:13.59,Default,,0000,0000,0000,,The next step for us was of course\Nto test our device on actual people.
Dialogue: 0,0:05:13.59,0:05:16.68,Default,,0000,0000,0000,,So we recruited about 100 presbyopes\Nand had them test our device
Dialogue: 0,0:05:16.68,0:05:18.39,Default,,0000,0000,0000,,while we measured their performance.
Dialogue: 0,0:05:18.39,0:05:21.72,Default,,0000,0000,0000,,What we saw convinced us right then\Nthat autofocals were the future.
Dialogue: 0,0:05:21.72,0:05:23.63,Default,,0000,0000,0000,,Our participants could see more clearly,
Dialogue: 0,0:05:23.63,0:05:25.02,Default,,0000,0000,0000,,they could focus more quickly
Dialogue: 0,0:05:25.02,0:05:28.03,Default,,0000,0000,0000,,and they thought it was an easier\Nand better focusing experience
Dialogue: 0,0:05:28.03,0:05:29.46,Default,,0000,0000,0000,,than their current correction.
Dialogue: 0,0:05:29.46,0:05:30.46,Default,,0000,0000,0000,,To put it simply,
Dialogue: 0,0:05:30.46,0:05:31.60,Default,,0000,0000,0000,,when it comes to vision,
Dialogue: 0,0:05:31.60,0:05:34.81,Default,,0000,0000,0000,,autofocals don't compromise\Nlike static corrections in use today do.
Dialogue: 0,0:05:34.81,0:05:36.76,Default,,0000,0000,0000,,But I don't want to get ahead of myself.
Dialogue: 0,0:05:36.76,0:05:39.50,Default,,0000,0000,0000,,There's a lot of work\Nfor my colleagues and me left to do.
Dialogue: 0,0:05:39.50,0:05:41.95,Default,,0000,0000,0000,,For example, our glasses are a bit --
Dialogue: 0,0:05:41.95,0:05:42.95,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:05:42.95,0:05:44.46,Default,,0000,0000,0000,,bulky, maybe?
Dialogue: 0,0:05:44.46,0:05:47.70,Default,,0000,0000,0000,,And one reason for this\Nis that we used bulkier components
Dialogue: 0,0:05:47.70,0:05:50.49,Default,,0000,0000,0000,,that are often intended\Nfor research use or industrial use.
Dialogue: 0,0:05:50.49,0:05:52.75,Default,,0000,0000,0000,,Another is that we need\Nto strap everything down
Dialogue: 0,0:05:52.75,0:05:56.48,Default,,0000,0000,0000,,because current eye-tracking algorithms\Ndon't have the robustness that we need.
Dialogue: 0,0:05:56.78,0:05:58.05,Default,,0000,0000,0000,,So moving forward,
Dialogue: 0,0:05:58.05,0:06:00.56,Default,,0000,0000,0000,,as we move from a research\Nsetting into a start-up,
Dialogue: 0,0:06:00.56,0:06:02.62,Default,,0000,0000,0000,,we plan to make future autofocals
Dialogue: 0,0:06:02.62,0:06:05.17,Default,,0000,0000,0000,,eventually look a little bit more\Nlike normal glasses.
Dialogue: 0,0:06:05.17,0:06:06.17,Default,,0000,0000,0000,,For this to happen,
Dialogue: 0,0:06:06.17,0:06:08.55,Default,,0000,0000,0000,,we'll need to significantly improve
Dialogue: 0,0:06:08.55,0:06:10.67,Default,,0000,0000,0000,,the robustness\Nof our eye-tracking solution.
Dialogue: 0,0:06:10.67,0:06:14.54,Default,,0000,0000,0000,,We'll also need to incorporate smaller\Nand more efficient electronics and lenses.
Dialogue: 0,0:06:14.92,0:06:17.21,Default,,0000,0000,0000,,That said, even with\Nour current prototype,
Dialogue: 0,0:06:17.21,0:06:19.76,Default,,0000,0000,0000,,we've shown that today's\Nfocus-tunable lens technology
Dialogue: 0,0:06:19.76,0:06:23.34,Default,,0000,0000,0000,,is capable of out-performing\Ntraditional forms of static correction.
Dialogue: 0,0:06:23.34,0:06:24.89,Default,,0000,0000,0000,,So it's only a matter of time.
Dialogue: 0,0:06:25.13,0:06:27.16,Default,,0000,0000,0000,,It's pretty clear that in the near future,
Dialogue: 0,0:06:27.16,0:06:30.17,Default,,0000,0000,0000,,instead of worrying about which pair\Nof glasses to use and when,
Dialogue: 0,0:06:30.17,0:06:32.72,Default,,0000,0000,0000,,we'll be able to just focus\Non the important things.
Dialogue: 0,0:06:33.69,0:06:34.69,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:06:34.69,0:06:36.44,Default,,0000,0000,0000,,(Applause)