25-08-2011, 10:48 AM
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THE HUMAN EYE
We are able to see because light from an object can move through space and reach our eyes.
Once light reaches our eyes, brain orders to detect the appearance, location and movement of the objects we are sighting at.
Lens : is a transparent, biconvex structure in the eye that helps to refract light to be focused on the retina.
Iris : is responsible for controlling the amount of light reaching the retina.
Pupil : is a hole located in the center of the iris of the eye that allows light to enter the retina.
Cornea : is the transparent front part of the eye that contributes on the focusing power.
Retina : is a light-sensitive tissue where image is obtained, which serves much the same function as the film in a camera.
Macula : is an oval-shaped yellow spot, responsible for central, high resolution vision.
Optic nerve : transmits visual information from the retina to the brain.
Light Sensitive Cells in Retina
Rod Cells(Rods):
Rods operate in poor light or at night.
Cone Cells:
Used in colour vision and in close precision work like reading.
Very few in number and are more concentrated in the centre of the retina (the macula)
Eye Diseases
Retinitis pigmentosa : group of hereditary diseases of the retina of the eye caused by a breakdown in the function of the rods or the cones in some part of the retina.
Macular degeneration : wearing out of the retinal pigment epithelium (RPE).
What Is a Bionic Eye?
Bionic Eye is an experimental visual device intended to restore functional vision in those suffering from partial or total blindness.
It rectifies Retinitis pigmentosa and Macular degeneration to an extent.
Founders behind the Bionic Eye
Researchers working for the Boston Retinal Implant Project have been developing the Bionic eye implant that could restore the eye sight of people who suffer from age related blindness.
Inspiration Behind Bionic Eye
Dr. Mark Humayun demonstrated that a blind person could be made to see light by stimulating the nerve ganglia behind the retina with an electrical current.
This test proved that the nerves behind the retina still functioned even when the retina had degenerated.
How does it restore sight?
The bionic eye uses a retinal implant connected to a video camera that converts images into electrical impulses that activate remaining retinal cells that then carry the signal back to the brain.
In this way the bionic eye mimics the function of the retina and restores sight.
METHODS
Bionic eye is implemented in different ways:
Using the ASR
Using the MARC system
Artificial Silicon Retina (ASR)
The ASR is a silicon chip 2 mm in diameter and 1/1000 inch in thickness.
It contains approximately 3,500 microscopic solar cells called "micro photodiodes," each having its own stimulating electrode.
Convert the light energy from images into thousands of electrical impulses to stimulate the remaining functional cells of the retina.
The ASR is powered solely by incident light and does not require wires or batteries
Original Size of ASR
MARC(MULTIPLE UNIT ARTIFICIAL RETINA CHIPSET) SYSTEM
Working of MARC System
An external camera acquires an image, encodes into data stream and transmitted via RF telemetry to an intraocular transceiver.
A data signal will be transmitted by modulating the amplitude of a higher frequency carrier signal.
The signal will be rectified and filtered, and the MARC extracts power, data, and a clock signal. The subsequently derived image will then be stimulated upon the patient’s retina.
Working of Bionic Eye
Advantages of Bionic Eye
Assist individuals suffering from retinitis pigmentosa (a genetic condition)
The technology may enable people to recognize faces and facial expressions.
The bionic eye will be affective for individuals who once had sight, since their brain knows how to process visual information.
Advantages of Bionic Eye
Advantages : water-proof and corrosion- proof (The chip is enclosed in a titanium casing)
Expected Durability : 10 years
Disadvantages of Bionic Eye
This technology till now will not help glaucoma patients.
The unfortunate people who were born blind do not have the neurological capability to process the data received via the wire.
The optic nerve must be at least partly functional or else the data will not be fully processed.
CONCLUSION
Bionic devices are being developed to do more than replace defective parts.
Providing power to run bionic implants and making connections to the brain's control system pose the two great challenges for biomedical engineering.
We are now looking at devices like bionic arms, tongues, noses etc.
THE HUMAN EYE
We are able to see because light from an object can move through space and reach our eyes.
Once light reaches our eyes, brain orders to detect the appearance, location and movement of the objects we are sighting at.
Lens : is a transparent, biconvex structure in the eye that helps to refract light to be focused on the retina.
Iris : is responsible for controlling the amount of light reaching the retina.
Pupil : is a hole located in the center of the iris of the eye that allows light to enter the retina.
Cornea : is the transparent front part of the eye that contributes on the focusing power.
Retina : is a light-sensitive tissue where image is obtained, which serves much the same function as the film in a camera.
Macula : is an oval-shaped yellow spot, responsible for central, high resolution vision.
Optic nerve : transmits visual information from the retina to the brain.
Light Sensitive Cells in Retina
Rod Cells(Rods):
Rods operate in poor light or at night.
Cone Cells:
Used in colour vision and in close precision work like reading.
Very few in number and are more concentrated in the centre of the retina (the macula)
Eye Diseases
Retinitis pigmentosa : group of hereditary diseases of the retina of the eye caused by a breakdown in the function of the rods or the cones in some part of the retina.
Macular degeneration : wearing out of the retinal pigment epithelium (RPE).
What Is a Bionic Eye?
Bionic Eye is an experimental visual device intended to restore functional vision in those suffering from partial or total blindness.
It rectifies Retinitis pigmentosa and Macular degeneration to an extent.
Founders behind the Bionic Eye
Researchers working for the Boston Retinal Implant Project have been developing the Bionic eye implant that could restore the eye sight of people who suffer from age related blindness.
Inspiration Behind Bionic Eye
Dr. Mark Humayun demonstrated that a blind person could be made to see light by stimulating the nerve ganglia behind the retina with an electrical current.
This test proved that the nerves behind the retina still functioned even when the retina had degenerated.
How does it restore sight?
The bionic eye uses a retinal implant connected to a video camera that converts images into electrical impulses that activate remaining retinal cells that then carry the signal back to the brain.
In this way the bionic eye mimics the function of the retina and restores sight.
METHODS
Bionic eye is implemented in different ways:
Using the ASR
Using the MARC system
Artificial Silicon Retina (ASR)
The ASR is a silicon chip 2 mm in diameter and 1/1000 inch in thickness.
It contains approximately 3,500 microscopic solar cells called "micro photodiodes," each having its own stimulating electrode.
Convert the light energy from images into thousands of electrical impulses to stimulate the remaining functional cells of the retina.
The ASR is powered solely by incident light and does not require wires or batteries
Original Size of ASR
MARC(MULTIPLE UNIT ARTIFICIAL RETINA CHIPSET) SYSTEM
Working of MARC System
An external camera acquires an image, encodes into data stream and transmitted via RF telemetry to an intraocular transceiver.
A data signal will be transmitted by modulating the amplitude of a higher frequency carrier signal.
The signal will be rectified and filtered, and the MARC extracts power, data, and a clock signal. The subsequently derived image will then be stimulated upon the patient’s retina.
Working of Bionic Eye
Advantages of Bionic Eye
Assist individuals suffering from retinitis pigmentosa (a genetic condition)
The technology may enable people to recognize faces and facial expressions.
The bionic eye will be affective for individuals who once had sight, since their brain knows how to process visual information.
Advantages of Bionic Eye
Advantages : water-proof and corrosion- proof (The chip is enclosed in a titanium casing)
Expected Durability : 10 years
Disadvantages of Bionic Eye
This technology till now will not help glaucoma patients.
The unfortunate people who were born blind do not have the neurological capability to process the data received via the wire.
The optic nerve must be at least partly functional or else the data will not be fully processed.
CONCLUSION
Bionic devices are being developed to do more than replace defective parts.
Providing power to run bionic implants and making connections to the brain's control system pose the two great challenges for biomedical engineering.
We are now looking at devices like bionic arms, tongues, noses etc.
