How can Blind People Regain Vision with Retinal Implant?

May 31, 2012

Healthy Life



Blind People Regain Vision with Retinal Implant

Blind People Regain Vision with Retinal Implant


For the last couple of years, scientists from all fields are constantly working towards developing intelligent devices that can be implanted in the human body, performing the same functions as the organs. In other words, such mechanisms will be placed in your body that can help you to hear, taste, smell and even see if your genuine organs are no longer functional. A landmark of this type of research is the creation of the retinal implant.

At the Stanford University in the US, the retinal implant is undergoing development. If you have still not guessed what its function is, you will be surprised to know that by planting this chip like mechanism, blind people will be able to see again!

Even though the news is amazing, it may not come as a surprise because technology is advancing at a remarkable pace. So if small eye problems could be fixed by applying spectacles and contact lens (such as the one day acuvue moist), blindness will soon be cured using retinal implants.

Before discussing how the retinal implant can help blind people regain vision, it is important to know the causes of blindness.


How Does the Eye Work?

In simple terms, the eye works just like a camera. The retina is located at the back of the eye, and it focuses the light falling on an object to realize its image. It is composed of different layers. The light enters first into the nerve fiber layer and the ganglion cell layer. Most of the healthy and supportive blood vessels of the retina are located under these layers.


The nerve starts at this point by picking up the flashes of a collected image from the retina and transmitting them to the brain. Photoreceptor cells, called rods and cones, receive this light and they transform it into nerve impulses. These are processed by the retina and sent via the nerve fibers to the brain. The fibers then leave the eyeball at the Blind spot and reach the brain through the optic nerve.


What Causes Blindness?

There are many disorders related to the retina. They include:

  • Age-related macular degeneration
  • Retinitis pigmentosa
  • Diabetic retinopathy

They, most of the time, involve blockage to light accumulation, possibly leading to blindness. Some of these disorders do not have a known cure, such as retinitis pigmentosa. In this disorder there is a slow, but eventual, damage to the rods within the retina that ultimately leave only the central fovea intact.


The Two Implanting Approaches

The task of restoring sight is extremely difficulty. Not only the engineering and electronic aspects need to be worked on, the surgical maneuvers also have to be developed.

Two approaches are being used here. First is the sub retinal implanting at the level of the photoreceptors. Thousands of photodiodes are collected in a sheet and linked to microelectrodes. These subsequently move the ganglion cells (output neurons) in the retina. The light shining on this collection produces a current that depolarizes the ganglion cells through these micro-electrodes.


The second method is the epiretinal implant on the inner and the opposite layer of the retina. In this approach, an external camera and processing unit are linked to a readout chip that is securely places to the inner retina, at the level of the ganglion cells.


The Complexity of the Procedure

The retina is located at the back of the eye and is only 0.5 mm thick. Experts claim that it is the most complex sensory organ in the human body. That is why the retinal implant is a highly difficult and sensitive procedure. The retina is composed of various cells such the photoreceptors, bipolar cells, horizontal cells and ganglion cells. The vision can be restored through the transduction of photons by the photoreceptors, which contains some unique such as hyper polarization.


Both approaches of implanting devices in eye are challenging. The biggest one is being able to maintain internal pressure in the eye and contrast the brightness of the surgical site during the procedure. Once the implant is, there is ample space between the sub retinal implant collection and the ganglion cells to simulate these cells. Even in this case, many of the other significant neuronal components that refine the retinal image in regular eyesight are bypassed.


How can Blind People Regain Vision with Retinal Implant?

This site is for information and support only and NOT a substitute for professional diagnosis and treatment!

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