By Dr. Mark S. Siegel
News stories about a ‘bionic eye transplant’ have gotten a lot of attention, but what is the reality of new technology for restoring sight to some blind patients? The Argus II Retinal Prosthesis System has sometimes been called a ‘bionic eye transplant.’ Right now it is not possible to transplant an entire human eye – only corneas and some other specific eye tissues can be transplanted. And there is no electronic replacement for the whole eye.
The Argus II is a three-part device that allows some perception of light and motion in patients who have lost their vision due to retinitis pigmentosa. Surgery is done to place a small electronic device on the patient’s retina. Later, the patient wears a camera mounted on a pair of glasses, and a portable video-processing unit. Images are taken in through the camera, processed, and then sent wirelessly to the implant in the patient’s retina. The implant stimulates the living cells in the retina, and the brain interprets these patterns as light. Over time, the patient learns to interpret the signals from the Argus II to see objects, their surroundings, and — in some cases — even read large-print text.
This is an exciting development, but the Argus II is not for everyone. It is only for patients who have no vision or almost no vision due to advanced retinitis pigmentosa (RP), a group of genetic disorders that affect the retina’s ability to respond to light. This inherited disease causes a slow loss of vision, beginning with decreased night vision and loss of peripheral (side) vision. Blindness ultimately results. Unfortunately, there is no cure for RP.
Patients must pass a careful medical screening to make sure there are no other physical reasons that they shouldn’t be given the implant. And patients should be aware that the Argus II does not restore complete, natural vision. The vision that is restored is black-and-white only, and does not include fine details.
Currently, only a handful of tertiary-care referral centers are performing the surgery. However, as more refinements are made to the Argus II and more progress is made, we may begin to see significant improvements in visual prognosis for RP and other debilitating eye disease.