Restoring Sight with Artificial Retinas

Researchers may have found a way to restore sight for those people suffering from macular degeneration and retinitis pigmentosa.  Scientists are testing artificial retinas and hope that these devices will help restore partial sight in those people who suffer from the most common causes of blindness such as macular degeneration.

In a government sponsored research program, researchers have created artificial retinas that can be implanted in the eye.  This will let individuals who had previously lost sight because of eye diseases such as macular degeneration be able to recognize faces and read large print.

According to Dr. Mark Humayun, a surgeon at the Doheny Eye Institute at the University of Southern California, Los Angeles, “Retinal prostheses represent the best near-term hope for individuals with incurable, blinding diseases of the outer retina.”

Test of a prototype artificial retina began on six patients in 2002, and these individuals were able to read foot-high letters after being totally blind previously.  These same patients could distinguish a plate from a cup, find doors and windows, and navigate around large objects.

A Sylmar, California company produced the devices for the U.S. Energy Department’s Artificial Retina Project.

The first generation artificial retina was named Argus One, and consisted of a tiny camera mounted on a pair of dark glasses and hip-mounted microprocessor.  The artificial retina relayed images to a silicon chip containing an array of 16 electrodes that had been surgically attached to the front of the retina.

After the artificial retina was implanted, patients could only see scattered arrays of light, and after training could detect straight lines and distinguish light areas from dark ones, as well as detect motion.  One retinitis pigmentosa patient could shoot a basketball through a hoop and tell wich way the offense wave moving on a tv screen.  Another patient could sport the shadow of his son as he passed by on a sidewalk.

The artificial retina, Argus One is still in use, but it is being succeeded by Argus Two, a smaller, more sophisticated artificial retina device, which will provide a much sharper image to the patients.

The newer device will be tested on 17 patients

Researchers are continuing to develop more sophisticated artificial retinas, hoping to have the devices contain many more electrodes and be contained on a thin, flexible film that will curve to fit the shape of the retina.  Work on this new artificial retina is scheduled to begin in 2011.

Artificial retinas are still experimental and won’t be available for commercial use for years.  The devices will cost at least $30,000 but researchers are optimistic that these artifical retinas will be viable treatments in the future.