HealthWACH: Bionic Eyes
Wed, 12 Mar 2014 02:00:00 GMT — COLUMBIA (WACH) - Retinitis pigmentosa (RP) is an eye disease in which there is damage to the retina. The retina is the layer of tissue at the back of the inner eye. It converts light images to nerve signals, and then sends those signals back to the brain. This can cause decreased vision at night or in low light, loss of peripheral vision, and loss of central vision. Retinitis pigmentosa affects one in 4,000 people in the United States. Retinitis pigmentosa can run in families. The cells controlling night vision are most likely to be affected. However, in some cases, retinal cone cells are damaged the most. The main sign of the disease is the presence of dark deposits in the retina.
Symptoms usually start during young adulthood, although RP may be seen at any age and include night blindness and loss of peripheral vision. Symptoms may not necessarily mean you have the disease, but if you experience one or more, you should contact your eye doctor for a complete eye exam.
There are currently very few treatments available for RP. Sometimes, the degeneration can be slowed to preserve vision for a longer time. Genetic studies of RP are a significant factor in finding a cure or prevention for this disease.
The bionic eye, also known as the Argus II system, can restore vision that was once considered permanently lost. The retinal implant restores visual impulses. The FDA approved the device in 2013 for use in adults 25 years or older. It does not restore normal 20-20 vision, but a patient with the device may be able to follow the lines of a crosswalk or sort laundry. After the implant surgery the patient wears glasses with an attached camera and a portable video processor. The video camera inside the patient's glasses captures a scene. The video is then sent to the computer, where it is processed and transformed into instructions that are sent back to the glasses. The instructions are transmitted wirelessly to an electrode array implanted on the retinal surface. Small pulses of electricity are emitted. These pulses bypass the damaged photo receptors and stimulate the retina's remaining healthy cells. The visual information is transmitted along the optic nerve to the brain. This creates the perception of light. Patients can learn to interpret these visual patterns with their retinal implant. The chip has 60 pixels; so when stimulated the patient can see flashes of light of high contrast items, certain colors, large letters and they can sort objects. The bionic eye is intended for patients with severe to profound RP.