Macular Degeneration Research and The Artificial Retina
Macular degeneration and retinitis pigmentosa destroy the light-sensing
cells (photoreceptors) in the retina, a multilayered membrane located at
the back of the eye. Unfortunately, these cells do a poor job of repairing
themselves and no effective treatments exist, so these individuals are
forced to accept their condition and adapt to life in a sightless world.
Vision loss due to retinal disease affects some 6 million Americans and 25
million people worldwide. With an aging population living longer, the
number of those affected will continue to grow and, by some estimates, may
even triple by 2025, creating a virtual pandemic of vision loss.
Normal vision begins when light enters and moves through the eye to strike
specialized photoreceptor (light-receiving) cells in the retina called
rods and cones. These cells convert light signals to electric impulses
that are sent to the optic nerve and the brain.
Retinal diseases like age-related macular degeneration and retinitis
pigmentosa destroy the photoreceptor cells. The artificial retina device
bypasses these cells to transmit signals directly to the optic nerve.
The device consists of a tiny camera and microprocessor mounted in
eyeglasses, a receiver implanted behind the ear, and an electrode-studded
array that is tacked to the retina. A wireless battery pack worn on the
belt powers the entire device.
The camera captures an image and sends the information to the
microprocessor, which converts the data to an electronic signal and
transmits it to the receiver. The receiver sends the signals through a
tiny cable to the electrode array, stimulating it to emit pulses. The
pulses travel through the optic nerve to the brain, which perceives
patterns of light and dark spots corresponding to the electrodes
stimulated. Patients learn to interpret the visual patterns produced.
Who Is Eligible For The Artificial Retina?
Who is eligible for a retinal implant? The devices discussed in this video
are experimental and not yet available to the public.
Studies are now being conducted at the Doheny Eye Institute at the
University of Southern California Medical Center. Although enrollment is
not currently open, to be eligible for consideration as a candidate for
future studies patients should call Second Sight at 818.833.5000 for more
information and ask for the Clinical Research Department.