Visual prosthetics let blind people “see” letters, shapes

Visual prosthetics let blind people “see” letters, shapes

Imagine a device implanted in the brain that lets blind people visually perceive shapes.

A person with one of these visual prosthetics doesn’t “see,” exactly. Rather, they experience what are called phosphenes, flashes of light that appear before the eyes. This happens when a person’s visual cortex, the part of the brain that processes sight, receives electrical stimulation.

Researchers from Texas and California say they have used visual prosthetics to create phosphenes in the shapes of letters that some blind people can see, in a manner of speaking. The technique only works for people with a functional visual cortex. Many people blinded by an eye injury or optic nerve injury can have an intact visual cortex.

An article recently published in the journal Cell describes the researchers’ work.

The new technique of moving an electrical current between the electrodes on the prosthetic succeeded where past experiments have failed. Think of tracing a letter on the palm of a hand.

In prior studies, electrodes in the shape of a letter were activated simultaneously, but there was no movement of electricity between the electrodes. In those trials, subjects said they didn’t see a shape, just a bunch of scattered dots.

For a person who has lost eyesight, being able to “see” shapes and letters might be life-changing. The study authors note the technology might be used to create a guide to the location of objects in a room, for example. Visual prosthetics might someday let blind people read without Braille or enjoy the beauty of a painting.

The method needs more testing, of course, but at this point, the possibilities seem … electrifying.

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