Glasses are a brilliant technology. They're so good, in fact, that they've gone relatively unchanged since the first iterations were used in 13th century. Of course, since then we’ve made improvements---today we can even stick little lenses in our eyes!---but as far as things that rock the optical world go, it’s been pretty quiet. Maybe not for long.
Researchers from MIT and the University of California, Berkeley have created a prototype for a new display technology that can automatically correct for vision defects. Think of it as glasses for your iPad. Or your phone, or your car dashboard or any number of screen-based devices you have in your life. The point being, someday in the not too distant future you won’t need to wear glasses anymore to do certain tasks.
Visual defects are often the result of not being able to focus on an image at a particular distance. This early prototype, which is basically a transparent overlay with pinholes that can be clipped onto a preexisting screen, simulates showing an image at the correct focal distance for individual viewers. “We want to be able to show you the virtual image that’s floating outside the physical device in a range where you can actually focus,” says Gordon Wetzstein, a former research scientist at MIT (now at Stanford) who worked on the project.
Funnily, the technology is an extension of the group’s research on how to view 3-D displays without using glasses. “It’s interesting that we’ve been in this mindset of wanting to get rid of glasses for 3-D but not for the bigger problem of people having to wear glasses for seeing regular 2-D images,” Wetzstein says.
To make current forms of 3-D work, a display will show different images to the left and right eye. This vision-correcting display, rather, will project slightly different images to various parts of the viewer’s pupil at different angles. The biggest issue in doing this is to make a simulated pixel (the one that corrects for your visual defect), it takes multiple pixels on the actual device. MIT explains: "The physical pixels projecting light to the right side of the pupil have to be offset to the left, and the pixels projecting light to the left side of the pupil have to be offset to the right."
In theory, this could drastically lower the resolution of what you end up seeing. Not good. But researchers were able to produce transparencies patterned with pinholes that direct light to the correct perspective (according to whatever visual defect someone might have). This overlay method is clearly an academic prototype, but Wetzstein says that this same effect could be incorporated into actual glass displays by a technique that uses two LCD displays in parallel to each other.
Wetzstein imagines that eventually we’ll simply have to enter our prescription into our devices, and software will tweak the display settings according to our personal needs. “We’ve already seen that our mobile devices can give us personalized experiences, in a way our vision correcting display technology just takes this one step further,” he says. To make that work, all you'll really need is a front-facing camera that can track your eye movement (though something like the Amazon Fire with its one front-facing camera and four motion-tracking cameras is ideal).
Right now, the displays only work on individual users, so don’t expect your movie-going experience to change much. And to that point, Wetzstein is quick to say this won’t make everything in your world sharper, just those screens. Still, it's a start. Some applications are obvious---the previously mentioned gadgets and even dashboard-mounted displays, for example---but more intriguing than those ideas is how it could be used in the cheaper cellphones that are making their way to less developed countries around the world. “If we can use these phones and have technology integrated that can help people see or read better, it would be very interesting to see how it could make an impact on people’s lives,” he says.
