Researchers from the MIT Media Laboratory and the University of California have developed a new display screen that automatically corrects vision defects, making it unnecessary for users to wear glasses or contact lenses.
“The first spectacles were invented in the 13th century,” said Gordon Wetzstein, one of the display's creators. “Today, of course, we have contact lenses and surgery, but it’s all invasive in the sense that you either have to put something in your eye, wear something on your head, or undergo surgery. We have a different solution that basically puts the glasses on the display, rather than on your head. It will not be able to help you see the rest of the world more sharply, but today, we spend a huge portion of our time interacting with the digital world.”
The display's technology is based off the Camera Culture group's glasses-free 3D technology. The 3D display projects slightly different images to the right and left eyes. The vision-correcting display projects slightly different images to different parts of the pupil.
When a person has a vision defect, there is a mismatch in the eye's focal distance and the distance of the object the eye is trying to focus on. The new display can simulate an image at the right focal displace, which would be somewhere between the display and the user's eyes.
As the MIT News office notes, the process of automatically correct vision defects is quite complicated.
"The difficulty with this approach is that simulating a single pixel in the virtual image requires multiple pixels of the physical display," the article reads. "The angle at which light should seem to arrive from the simulated image is sharper than the angle at which light would arrive from the same image displayed on the screen. So 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."
Using multiple pixels to simulate a single pixel would reduce the image resolution. However, the research team ran into a similar issue with their 3D displays, which they fixed by making algorithms to exploit the redundancy to allow individual pixels to be projected simultaneously in different viewing angles. For the vision-correcting displays, the research team adapted a similar algorithm to ensure the loss of resolution is as small as possible.
Wetzstein believes they will be able to combine the technologies for the 3D and the vision-correcting displays for an entirely glasses-free experience. Eventually, they will also produce a display that can diagnose vision effects, so the display could determine the user's prescription and use that information to automatically correct the display.