The purpose of this report is to identify and briefly describe the development of the bionic eye. Document the process of how the bionic eye works and analyse the for and against arguments of the bionic eye.
Close to 40 million people in the world have been affected by blindness. Many of these patients can be successfully treated with surgery or medication. Some pathologies cannot be corrected with existing treatments. When light receiving photoreceptor, cells start failing due to, retinitis pigmentosa, or when the optic nerve is damaged because of glaucoma or head trauma, no surgery or medicine can restore the lost vision. In some cases, the only option maybe a visual prosthesis.
A bionic eye restores some sight for those with severe vision loss and replaces the function of the retina. The bionic eye is a retinal implant connected to a video camera that converts images into electrical impulses that activate the remaining retinal cells then carry the signal back to the brain. The bionic eye is an electrical prosthesis surgically implanted into the human eye which allows light to process to the brain for people with severe damage to the retina. The sensitive tissue layer found within the inner eye is the retina which changes images from the outside world into neural impulses which is then passed along the optic nerve to the thalamus and then to the primary visual cortex. The visual cortex is located in the occipital lobe of the brain. For the bionic eye to work the individual must have been able see at some point in their life, for the nerve connections in the brain to function the device.
In addition to the neurons in the eye, also target the brain to stimulate artificial vision in humans as researches have found.
A pair of glasses fitted with a video camera captures images and processes the images. They are then sent wirelessly to a bionic implant at the back of the eye that stimulates dormant optic nerves to generate points of light that forms a basis of an image in the brain.
Development of the Bionic Eye
In 1755, French physician and scientist Charles Leroy discharged the static electricity into a blind patient’s body using two wires, one other around the leg and the other tightened around the head just above the eyes. This was the first time an electrical device, serving as a simple prosthesis, restored a flicker of visual perception.
In 1929, early research in epileptic patients with persistent seizures by German neurologists and neurosurgeons Otfrid Förster.
In 1931, Fedor Krause and Heinrich Schum presented that electrical stimulation of an occipital pole, the most subsequent part the brains’ hemisphere, lead to sensations of light flashes.
By the mid-1950s, Americans John C. Button, an osteopath and later MD, and Tracy Putnam, then Chief of Neurosurgery at Cedars-Sinai Hospital in Los Angeles, have implanted stainless steel wires connected to a simple stimulator into the cortices of four people who were blind, and the patients afterward reported seeing flashes of light.
In 1968 England produced the first functional cortical visual prosthesis, when Giles Brindley, a physiologist, and Walpole Lewin, a neurosurgeon, both at the Cambridge University, implanted 80 surfaced electrodes fixed in a silicone cap in the right occipital cortex of the patient. Each electrode connected to one of 80 corresponding extracranial radio receivers, which created simple distinctly located phosphene shapes. The patient could point with her hand to their location in her visual field.
Simple patterns emerged when more than one electrode at a time was stimulated. The subsequent aim of the late William H. Dobelle was to provide patients with visual images containing separate sets of phosphenes (artificial vision). Dobelle had begun studying electrical stimulation of the visual cortex. In the late 1960s sighted patients were undergoing surgery to remove occipital lobe tumours. Then a surface electrode arrays were first temporarily implanted, then permanently, in the visual cortices of several blind volunteers.
Early 2000s is when the technology became available to connect a miniature portable computer and camera to the electrodes for practical conversion of real world sights into electrical signals. With the result in cortical stimulus. A patient could recognise large print letters and the outline of images.
However, the surface electrodes used in these early cortical prostheses required large electrical currents which risked triggering epileptic seizures or debilitating migraines. These devices also required external cables that penetrate the skull, risking infection. Today, the use of wireless technology, several groups are aiming to improve cortical vision prostheses, to provide benefits to millions of people with currently incurable blindness.
In 2012 the first bionic eye was implanted and reported. Patients that have suffered from profound vision loss because of retinitis pigmentosa. By the Australian company bionic vision company, the first model was created. Improved models have allowed patients glimpses of their environment.
The development of bionic vision devices is accelerating rapidly due to collaborative efforts using the latest silicon chip and electrode design, computer vision processing algorithms, and wireless technologies.