On May 25, researchers at the Hong Kong University of Science and Technology have designed the world’s first 3D artificial eye, which may be clearer than the human eye.
If all goes well, it is expected to bring sight to millions of people within five years.
The artificial eye creates images through a variety of tiny sensors that mimic the light-detecting photoreceptors of the human eye, the report said. The sensor is packaged in aluminum and tungsten films, forming a hemisphere with a diameter of over 2 cm, mimicking the human retina.
What is the function of this 3D artificial eyeball?
According to Prof. Zhiyong Fan from the Hong Kong University of Science and Technology, the size of the bionic eye is comparable to that of the human eye, and the structure of the bionic eye is also highly similar to that of the human eye. When a single nanowire is electrically addressed, it has the potential to achieve high imaging resolution. The image is transformed by a multitude of tiny sensors housed in a hemispherical membrane made of aluminum and tungsten that mimics the human retina, which could theoretically exceed the high-resolution imaging of the human eye.
Not only that, this artificial retina is sensitive to all frequencies of light in the visible spectrum, and it responds in as little as 19.2 milliseconds after receiving a light stimulus, and then returns to an inactive state in 23.9 milliseconds, 40 times longer than the photoreceptor cells in the human retina. -150ms response and recovery time is much shorter.
Experts say the technology could be used in a wide range of applications. In addition to helping individuals improve their eyesight, other biomimetic light-sensitive devices can be made. Animal and clinical trials are currently being planned, and it is expected to be ready for use within five years.
It is reported that in addition to helping people improve vision, this bionic eye technology can also be used to make other biomimetic photosensitive devices, and animal and clinical trials are currently being planned.
Structure and function of the eyeball
The human eye is an approximate spherical body, with an anterior and posterior diameter of about 23-24 mm and a lateral diameter of about 20 mm, which usually becomes the eyeball. The eyeball is composed of two parts: the refractive system and the photoreceptor system.
The wall of the eyeball consists of three membranes with different textures:
(1) Cornea and sclera. The outermost layers of the eyeball wall are the cornea and sclera. The cornea is in front of the eyeball, accounting for about 1/6 of the entire eyeball wall area. It is a transparent film with a thickness of about 1mm and a refractive index of 1.336. The role of the cornea is to focus the light entering the eye, that is, to refract and concentrate the light entering the eye.
The sclera is the outermost white and tough membrane in the middle and rear, accounting for about 5/6 of the entire eyeball wall area, with a thickness of about 0.4-1.1mm, which is our “white of the eye”, and its role is to protect the eyeball.
(2) The iris and choroid. The iris, choroid, and ciliary body make up the middle layer of the eyeball wall. The iris is the annular membrane layer behind the cornea that divides the space between the cornea and the lens into two parts, the anterior chamber and the posterior chamber. The inner edge of the iris, called the pupil, acts like the aperture on a camera lens, automatically controlling the amount of incoming light.
The iris can contract and stretch, so that the pupil dilates when the light is weak and shrinks when the light is strong, and the diameter can vary from 2 to 8 mm.
The ciliary body is formed by the thickening of the choroid behind the junction of the sclera and the cornea. It contains smooth muscle that supports the position of the lens and regulates the convexity (curvature) of the lens. The choroid has the widest range, close to the inner surface of the sclera, about 0.4mm thick, and rich in melanocytes. It is like a camera camera obscura, which can absorb stray light in the eyeball and ensure that the light only enters the eye from the pupil to form a clear image.
(3) Retina. This is the innermost transparent film of the eyeball wall, attached to the inner surface of the choroid, with a thickness of about 0.1 to 0.5 mm. There are a large number of visual photoreceptor cells, cone cells and rod cells on the retina, which is the photoreceptor part of the eye, and its function is like the photoreceptor material in the camera.
In the central part of the back of the eyeball, there is a particularly dense area of cells on the retina, which is yellow in color, called the macula, about 2 to 3 mm in diameter, and has a small fossa in the center of the macula, called the fovea, where the most vision is sharp place.
The macula is about 4mm away from the nasal side. There is a disc-shaped optic nerve head. Because it has no photoreceptor cells, it has no photoreceptive ability, so it is called a blind spot. Light signals from external objects form an image on the retina, where the inner segment of the optic nerve transmits information to the brain.
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