9:59:59.000,9:59:59.000 Every single one of us will lose, 9:59:59.000,9:59:59.000 or has already lost something[br]we rely on every single day. 9:59:59.000,9:59:59.000 I am of course talking about our keys. 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 Just kidding. 9:59:59.000,9:59:59.000 What I actually want to talk about[br]is one of our most important senses: 9:59:59.000,9:59:59.000 vision. 9:59:59.000,9:59:59.000 Every single day we each lose[br]a little bit of our ability 9:59:59.000,9:59:59.000 to refocus our eyes 9:59:59.000,9:59:59.000 until we can't refocus at all. 9:59:59.000,9:59:59.000 We call this condition presbyopia, 9:59:59.000,9:59:59.000 and it affects two billion[br]people worldwide. 9:59:59.000,9:59:59.000 That's right, I said billion. 9:59:59.000,9:59:59.000 If you haven't heard of presbyopia, 9:59:59.000,9:59:59.000 and you're wondering, "Where are[br]these two billon people?" 9:59:59.000,9:59:59.000 here's a hint before[br]I get into the details. 9:59:59.000,9:59:59.000 It's the reason why people[br]wear reading glasses 9:59:59.000,9:59:59.000 or bifocal lenses. 9:59:59.000,9:59:59.000 I'll get started by describing the loss[br]of refocusing ability 9:59:59.000,9:59:59.000 leading up to presbyopia. 9:59:59.000,9:59:59.000 As a newborn, 9:59:59.000,9:59:59.000 you would have been able to focus[br]as lose as six-and-a-half centimenters 9:59:59.000,9:59:59.000 if you wish to. 9:59:59.000,9:59:59.000 By your mid-20s, you have about[br]half of that focusing power left. 9:59:59.000,9:59:59.000 10 centimeters or so, 9:59:59.000,9:59:59.000 but close enough that you never[br]notice the difference. 9:59:59.000,9:59:59.000 By your late-40s though, 9:59:59.000,9:59:59.000 the closest you can focus[br]is about 25 centimeters, 9:59:59.000,9:59:59.000 maybe even farther. 9:59:59.000,9:59:59.000 Losses in focusing ability[br]beyond this point 9:59:59.000,9:59:59.000 start effecting near-vision[br]tasks like reading, 9:59:59.000,9:59:59.000 and by the time you reach age 60, 9:59:59.000,9:59:59.000 nothing within a meter[br]radius of you is clear. 9:59:59.000,9:59:59.000 Right now some of you[br]are probably thinking, 9:59:59.000,9:59:59.000 that sounds bad but he means you[br]in a figurative sense, 9:59:59.000,9:59:59.000 only for the people that actually[br]end up with presbyopia. 9:59:59.000,9:59:59.000 But no, when I say you, I literally mean[br]that every single one of you 9:59:59.000,9:59:59.000 will someday be presbyopic[br]if you aren't already. 9:59:59.000,9:59:59.000 That sounds a bit troubling. 9:59:59.000,9:59:59.000 I want to remind you that presbyopia[br]has been with us for all of human history 9:59:59.000,9:59:59.000 and we've done a lot of different[br]things to try and fix it. 9:59:59.000,9:59:59.000 So to start, let's imagine[br]that you're sitting at a desk reading. 9:59:59.000,9:59:59.000 If you were presbyopic, 9:59:59.000,9:59:59.000 it might look a little[br]something like this. 9:59:59.000,9:59:59.000 Anything close by,[br]like the magazine, will be blurry. 9:59:59.000,9:59:59.000 Moving on to solutions. 9:59:59.000,9:59:59.000 First, reading glasses. 9:59:59.000,9:59:59.000 These have lenses[br]with a single focal power 9:59:59.000,9:59:59.000 tuned so that near objects[br]come into focus. 9:59:59.000,9:59:59.000 But far objects necessary go out of focus, 9:59:59.000,9:59:59.000 meaning you have to constantly[br]switch back and forth 9:59:59.000,9:59:59.000 between wearing and not wearing them. 9:59:59.000,9:59:59.000 To solve this problem, 9:59:59.000,9:59:59.000 Benjamin Franklin invented[br]what he called "double spectacles." 9:59:59.000,9:59:59.000 Today we call those bifocals, 9:59:59.000,9:59:59.000 and what they let him do was see[br]far when he looked up 9:59:59.000,9:59:59.000 and see near when he looked down. 9:59:59.000,9:59:59.000 Today we also have progressive lenses[br]which get rid of the line 9:59:59.000,9:59:59.000 by smoothly varying the focal power[br]from top to bottom. 9:59:59.000,9:59:59.000 The downside to both of these[br]is that you lose field of vision 9:59:59.000,9:59:59.000 at any given distance 9:59:59.000,9:59:59.000 because it gets split up[br]from top to bottom like this. 9:59:59.000,9:59:59.000 To see why that's a problem, 9:59:59.000,9:59:59.000 imagine that you're climbing[br]down a ladder or stairs. 9:59:59.000,9:59:59.000 You look down to get[br]your footing but it's blurry. 9:59:59.000,9:59:59.000 Why would it be blurry? 9:59:59.000,9:59:59.000 Well, you look down, and that's[br]the near part of the lens, 9:59:59.000,9:59:59.000 but the next step was past arm's reach, 9:59:59.000,9:59:59.000 which for your eyes, counts as far. 9:59:59.000,9:59:59.000 The next solution I want to point out[br]is a little less common 9:59:59.000,9:59:59.000 but comes up a lot in contact lenses[br]or Lasik surgeries, 9:59:59.000,9:59:59.000 and it's called monovision. 9:59:59.000,9:59:59.000 And it works but setting up[br]the dominant eye to focus far 9:59:59.000,9:59:59.000 and the other eye to focus near. 9:59:59.000,9:59:59.000 Your brain does the work of intelligently[br]putting together the sharpest parts 9:59:59.000,9:59:59.000 from each eye's view, 9:59:59.000,9:59:59.000 but the two eyes see slightly[br]different things, 9:59:59.000,9:59:59.000 and that makes it harder[br]to judge distances binocularly. 9:59:59.000,9:59:59.000 So where does that all leave us? 9:59:59.000,9:59:59.000 It seems like we've come up with[br]a lot of different solutions 9:59:59.000,9:59:59.000 but none of them quite restore[br]natural refocusing. 9:59:59.000,9:59:59.000 None of them let you[br]just look at something 9:59:59.000,9:59:59.000 and expect it to be in focus. 9:59:59.000,9:59:59.000 But why? 9:59:59.000,9:59:59.000 Well, to explain that, we'll want[br]to take a look at the anatomy 9:59:59.000,9:59:59.000 of the human eye. 9:59:59.000,9:59:59.000 The part of the eye that allows us[br]to refocus to different distances 9:59:59.000,9:59:59.000 is called the crystalline lens. 9:59:59.000,9:59:59.000 There are muscles surrounding the lens[br]that can deform it into different shapes, 9:59:59.000,9:59:59.000 which in turn changes its focusing power. 9:59:59.000,9:59:59.000 What happens when someone[br]becomes presbyopic? 9:59:59.000,9:59:59.000 It turns out that the crystalline[br]lens stiffens to the point 9:59:59.000,9:59:59.000 that it doesn't really change[br]shape anymore. 9:59:59.000,9:59:59.000 Now, thinking back[br]on all the solutions I listed earlier, 9:59:59.000,9:59:59.000 we can see that they all have something[br]in common with the others 9:59:59.000,9:59:59.000 but not with our eyes, 9:59:59.000,9:59:59.000 and that is that they're all static. 9:59:59.000,9:59:59.000 It's like the optical equivalent[br]of a pirate with a peg leg. 9:59:59.000,9:59:59.000 What is the optical equivalent[br]of a modern prosthetic leg? 9:59:59.000,9:59:59.000 The last several decades have seen[br]the creation and rapid development 9:59:59.000,9:59:59.000 of what are called "focus-tunable lenses." 9:59:59.000,9:59:59.000 There are several different types. 9:59:59.000,9:59:59.000 Mechanically-shifting Alvarez lenses, 9:59:59.000,9:59:59.000 deformable liquid lenses 9:59:59.000,9:59:59.000 and electronically-switched, [br]liquid-crystal lenses. 9:59:59.000,9:59:59.000 Now these have their own tradeoffs, 9:59:59.000,9:59:59.000 but what they don't skimp on[br]is the visual experience. 9:59:59.000,9:59:59.000 Full field-of-view vision that can be[br]sharp at any desirable distance. 9:59:59.000,9:59:59.000 OK, great. 9:59:59.000,9:59:59.000 The lenses we need already exist; 9:59:59.000,9:59:59.000 problem solved, right? 9:59:59.000,9:59:59.000 Not so fast. 9:59:59.000,9:59:59.000 Focus-tunable lenses add a bit[br]of complexity to the equation. 9:59:59.000,9:59:59.000 The lenses don't have any way[br]of knowing what distance 9:59:59.000,9:59:59.000 they should be focused to. 9:59:59.000,9:59:59.000 What we really need are glasses[br]that, when you're looking far, 9:59:59.000,9:59:59.000 far objects are sharp, 9:59:59.000,9:59:59.000 and when you're looking near, 9:59:59.000,9:59:59.000 near objects come into focus 9:59:59.000,9:59:59.000 anywhere in your field of view[br]and without you having to think about it. 9:59:59.000,9:59:59.000 What I've worked on these last[br]few years at Stamford 9:59:59.000,9:59:59.000 is building that exact intelligence[br]around the lenses. 9:59:59.000,9:59:59.000 Our prototype borrows technology[br]from virtual and augmented reality systems 9:59:59.000,9:59:59.000 to estimate focusing distance. 9:59:59.000,9:59:59.000 We have an eye tracker that can help tell[br]what direction our eyes are focused in. 9:59:59.000,9:59:59.000 Using two of these, 9:59:59.000,9:59:59.000 we can directly triangulate[br]your gaze direction 9:59:59.000,9:59:59.000 to get a focus estimate. 9:59:59.000,9:59:59.000 Just in case though, 9:59:59.000,9:59:59.000 to increase reliability we also added[br]a distance censor. 9:59:59.000,9:59:59.000 The censor is a camera that looks[br]out at the world 9:59:59.000,9:59:59.000 and reports distances to objects. 9:59:59.000,9:59:59.000 We can again use your gaze direction[br]to get a distance estimate 9:59:59.000,9:59:59.000 for a second time. 9:59:59.000,9:59:59.000 We then fuse those two distance estimates 9:59:59.000,9:59:59.000 and update the focus-tunable[br]lens power accordingly. 9:59:59.000,9:59:59.000 The next step for us was of course[br]to test our device on actual people. 9:59:59.000,9:59:59.000 So we recruited about 100 presbyopes[br]and had them test our device 9:59:59.000,9:59:59.000 while we measured their performance. 9:59:59.000,9:59:59.000 What we saw convinced us right then[br]that autofocals were the future. 9:59:59.000,9:59:59.000 Our participants could see more clearly, 9:59:59.000,9:59:59.000 they could focus more quickly 9:59:59.000,9:59:59.000 and they thought it was an easier[br]and better focusing experience 9:59:59.000,9:59:59.000 than their current correction. 9:59:59.000,9:59:59.000 Put it simply: 9:59:59.000,9:59:59.000 when it comes to vision, 9:59:59.000,9:59:59.000 autofocals don't compromise[br]like static corrections in use today do. 9:59:59.000,9:59:59.000 But I don't want to get ahead of myself. 9:59:59.000,9:59:59.000 There's a lot of work for my colleagues[br]and me left to do. 9:59:59.000,9:59:59.000 For example, our glasses are a bit -- 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 bulky, maybe? 9:59:59.000,9:59:59.000 And one reason for this is that we used[br]bulkier components 9:59:59.000,9:59:59.000 that are often intended[br]for research use or industrial use. 9:59:59.000,9:59:59.000 Another is that we need to strap[br]everything down 9:59:59.000,9:59:59.000 because current eye-tracking algorithms[br]don't have the robustness that we need. 9:59:59.000,9:59:59.000 So moving forward, 9:59:59.000,9:59:59.000 as we move from a research[br]setting to a start-up, 9:59:59.000,9:59:59.000 we plan to make future autofocals 9:59:59.000,9:59:59.000 eventually look a little bit more[br]like normal glasses. 9:59:59.000,9:59:59.000 For this to happen, 9:59:59.000,9:59:59.000 we'll need to significantly improve 9:59:59.000,9:59:59.000 the robustness[br]of our eye-tracking solution. 9:59:59.000,9:59:59.000 We'll also need to incorporate smaller[br]and more efficient electronics and lenses. 9:59:59.000,9:59:59.000 That said, even with[br]our current prototype, 9:59:59.000,9:59:59.000 we've shown that today's[br]focus-tunable lens technology 9:59:59.000,9:59:59.000 is capable of out-performing[br]traditional forms of static correction. 9:59:59.000,9:59:59.000 So it's only a matter of time. 9:59:59.000,9:59:59.000 It's clear that in the near future, 9:59:59.000,9:59:59.000 instead of worrying about which pair[br]of glasses to use and when, 9:59:59.000,9:59:59.000 we'll be able to just focus[br]on the important things. 9:59:59.000,9:59:59.000 (Applause) 9:59:59.000,9:59:59.000 Thank you. 9:59:59.000,9:59:59.000 (Applause)