Vision impairment or blindness occurs due to retinal diseases, damage, or age-related macular degeneration of the optic nerve, the brain, or any part of the visual pathway between them. Retinal diseases are spread widely, and about 1.5 million people worldwide have retinitis pigmentosa, and 1/10 people (above 55) have age-related macular degeneration.
Eye gears for rectification and surgical removal of opaque or deteriorating corneas and replacement with donor transplants have been common medical practices. But a new revolutionary technique is emerging, named artificial vision, that allows blind people to see.
The first step in curing blindness, artificial vision, provides bionic eyes (aka retinal implant or artificial eye) to regenerate the lost vision. It provokes visual sensations in the brain by directly stimulating different parts of the optic nerve.
The bionic eye consists of electronic systems with image sensors, processors, receivers, radio transmitters, and retinal chips connected together in a single domain. It has an externally-worn camera close to a stimulator on the retina, optic nerve, or the visual cortex to manufacture perceptions in the visual cortex. This tiny device can be placed at the retina. Since the device is a silicon-based chip that delivers stimulation, which decodes radio signals. This signal transmits to the retinal ganglion cells, after that optical nerve, then to the brain.
Argus II, for instance, is a retinal implant with an electrode array with a small receiver. It is fixed around the eye and surgically implanted onto the retina. The electrode array sends and receives electrical signals (visual data) from the brain. This device can provide vision to patients who suffer from eye diseases like macular degeneration and retinitis pigmentosa, which disable the eyes’ cones, rods, and retina, distinguishing the light patterns before passing them on to the brain as nerve impulses
This retinal prosthesis system consists of:
- Digital-Camera: It is fixed into a pair of glasses. It captures the images and sends them to a microchip.
- Video processing Microchip: Its catalysis images (captured by digital camera) into electrical impulses, representing the light and dark patterns.
- Radio-Transmitter: It transmits the impulses into a receiver wirelessly.
- Radio-Receiver: It sends the impulse to the retinal implant.
- Retinal-Implant: it is a chip with an electrode array.
With the help of a bionic eye, a small camera captures the images and sends them to a microcontroller unit, where the data is converted into an electronic signal and re-transmit to a receiver on the eye. The receiver transmits them to the microelectrode array, where pulse emission is generated. These signals are sent to the brain through optic nerves, and the brain obtains light and dark patterns. Patients learn to understand these visual patterns, slowly enabling them to read and recognize facial impressions.
Advantages of bionic eyes
- It is very helpful for those suffering from retinitis pigmentosa (RP) and age-related macular degeneration (AMD).
- Helps to correct the vision and improve the quality of life of blind people.
- There is no surgical processor. It can be easily implanted
- No necessity to suffer from long and short sights.
- There is not any battery implanted in the body.
Disadvantages of bionic eyes
- This technique has many difficulties because the human eye is one of our body’s most sensitive organs. A small error can create disorder in the eye.
- The retina of every healthy human eye has 120 million rods and 6 million cones.
- Creating an artificial replacement for these cells is impractical and a risky task.
- Silicon is toxic to the body, and it reacts unfavorably with fluids in the eye.
- Not helpful for Glaucoma patients.
- Artificial retinas are too delicate for an ordinary person.
- There is no use for those people who are blind by birth.
- Implantation is complex and costs about 30,000$
- There is a doubt about how the brain will respond to the signals generated by artificial light sensors.