UC Berkeley researchers develop technology to correct screens for visual impairments

glasses
Clara Roig/Staff

People with vision problems may be able to forgo eyeglasses and contact lenses when viewing screens, with the development of a technology that alters devices to compensate for visual impairments.

Researchers at UC Berkeley developed a method using algorithms to change images pixel by pixel to adjust for the viewer’s specific visual aberration, an impairment that causes the eye to see a blurred or distorted image. The most recent iteration of the project includes a perforated screen in front of the display itself that makes the image clearer and improves the contrast.

“What’s really exciting is that this research will go beyond common vision problems and address some optical problems that cannot be corrected by eyeglasses,” said Brian Barsky, a professor of computer science and vision science and affiliate professor of optometry at UC Berkeley and the leader of the project.

While lower-order aberrations such as astigmatism can be easily corrected, higher-order aberrations often cause irregularities in the cornea and lens that are harder to compensate for with contact lenses or eyeglasses.

“These are extremely difficult to correct using optical elements,” said Fu-Chung Huang, who got his PhD in computer science at UC Berkeley and was lead author of the paper published on the project, in an email. He added that a computation-based correction made more sense than producing irregularly shaped eyeglasses, which would be the only way to correct higher-order aberrations with eyeglasses.

The current prototype uses images displayed on an iPod Touch that appear distorted but are sharp when viewed through a camera that is set to simulate a farsighted individual.

The technology would be especially useful for those who already wear contacts or eyeglasses but can’t read up close, as the display could be adjusted for the eye correction the individual is wearing and enable him or her to see the screen without reading glasses, Barsky said. It would also be helpful for people who view screens for long periods of time.

Although Barsky’s team is not the first to work on this problem, it was the first to see satisfying results by using multiple layers of LCD panels to achieve a sharper image and higher contrast than previous methods, Huang said.

“For the best results, the viewer should be at exactly the right position because the algorithms assume a particular point of view and gaze direction, but this is mitigated by the unconscious tendency of users to move around or move the display,” Barsky said in an email.

Martin Banks, a professor of optometry at UC Berkeley, was skeptical of the project’s use as a corrector for higher-order aberrations.

“The high aberrations are very position-dependent,” he said. “The correction could provide benefit when the eye is in exactly the right position, but when you make an eye movement, it wouldn’t work.”

UC Berkeley researchers Barsky, Huang and Austin Roorda worked with Massachusetts Institute of Technology researchers Gordon Wetzstein and Ramesh Raskar to produce the prototype, which will be presented at an international conference on computer graphics in August.

Contact Madeleine Pauker at [email protected].

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