Learn How the Retina is the Eye Behind Your Vision

Within your eyeball, the backside portion is known as retina and this occupies almost the entire rear portion of your eye.

This retina is made of millions of retinal cells, which can well be compared with microchips, and exactly here is where your vision takes place.

On capturing an image, the retinal cells will pass on the information in the form of message to the brain, which again can be compared with the bits of information in a computer getting transmitted to the main CPU, and these millions of flash messages will be carried by optic nerves to your brain.

The passage of information from your eyes to your brain can be compared to that of electrical impulses travelling through optic-fiber cables.

Once the brain receives the signals, your brain will decode the signals and you will be able to “see” things in its real terms. The decoding process of the brain will be similar to the decoding process of television or the telephone.

In order to transmit information to your brain, nature has provided your retina with two types of cells namely cones and rods, of which the cone cells perform better in bright light conditions and the rods are meant for performing better in dim light situations.

When it comes to the number of cells in your retina, the rods will outnumber the cones and there about 125 million rod type cells and around 7 million cone type cells.

The cone type cells are responsible for handling finer details and colors of your vision in bright light. On the other hand, the rod type cells are responsible for you to see things in dim light and they are little slow in their response unlike cone type cells.

The moment you enter into a dark room, you may not be able to see things clearly and only after pass of some time things will start appearing to your eyes and this is because of the rod type cells and their sluggish response.

Rod type cells also help you to distinguish between dark color and white color.

Your sight process is a well-refined and complicated process and in the process, first the cones and rods are further connected to another type of cell called a bipolar cell.

Bipolar cell’s job is to transmit the information or the pulses to the millions of ganglions and these ganglion cells in turn re-transmit the information to your brain.

In a healthy person there will be around 1.9 million of ganglion cells carrying out the job of sending information to your brain as and when you “see” things.

The job of bipolar cells is very important in your vision process and these cells are of two types namely magno cells and parvo cells.

Out of these two, magno cells constitute around 10 percent and the other parvo cells constitute the rest of the 90 percent in number.

In your vision process, magno cells are responsible for making you to see shapes and distinguish them and they also help you to see in dark and in dim light conditions.

To make it further clear, if you are able to find a black suit in your dark closet or able to find a coin in a poorly lit wooden floor, then it is with the help of magno cells present in your eye.

Any loss of such magno cells will make you to get impaired vision especially in reading and you may also tend to find difficulty in differentiating letters from spaces and breaks between words.

The parvo cells are responsible for finding the finer details such as texture in a painting, lines or colors in a painting, etc.

When compared to the cone and rod cells, the available ganglion cells are limited in numbers and hence more number of rod and cone cells, say thousands of them, are connected to each and every ganglion cell and that forms a well defined field around the ganglion cell.

Any loss of such ganglion cell will affect your vision in dim light first and you will also experience difficulty in differentiating contrast besides making things hazy or blurred vision. The symptoms will be very similar to your having cataract problem.

In your retina, the center portion will be concentrated with more of ganglion cells and this area is known and macula. The macular region is the actual area of your sight and any loss of ganglion cells or rod or cone type cells in this region will lead you to having defective vision and you may not be able to focus your sight on any particular object or area.

Any normal reading will be in need of fixing your sight focus on the letters and you may not be able to read or the letters may jump around under a condition where in you have degenerated macula.

Macular failure or degeneration of macular region is an age-related problem and hence the AMD or the age-related macular degeneration, is primarily a disease that affects mostly elderly people.

There will not be any macula degeneration in case of glaucoma patients and patients who suffer from glaucoma will experience loss of vision in their peripheral region initially.

Fortunately or unfortunately, the numbers of cells that are present in the peripheral area of vision are very less, and hence any loss of such cells will lead to loss of peripheral vision only.

This type peripheral vision loss is not that much debilitating when compared to that of loss of vision in the central area of macular region, and hence many aged people who are victims of AMD never bother about the loss of their peripheral vision, as the disability will not affect them in any real sense.

The center of the macular region is normally concentrated with cone type cells, which in turn get connected with its own ganglion cell.

This particular macular area of your eye is known as fovea and is very important as each and every cone cell is connected to individual ganglion cell and the area is the actual seat of your major eye vision.

Only with this particular fovea, will you be able to see things such as a bird perched on a tree branch or a kite flying atop a high building or the distant stars in the night or an airplane flying high in the deep blue sky.

You may be wondering how many high flying birds such as vultures and hawks are able to see precisely their prey in the ground and for your knowledge it is due to the presence of fovea only and all these birds have two foveas that make them to see from such great heights of even 10000 feet and things that are not visible for normal human eyes.

The most remarkable organ or the device with which you see is your eye and in the vision process, you eyes will make inverted images on your retina of what you see.

The miniscule inverted images on your retina will be formed on a continuous basis as you continue with your “seeing” act.

All these images will be either formed in slow manner or very fast manner depending upon the intensity of light source and your eyes’ fixating ability.

For instance, you may find it difficult to comprehend the figures in a dim source of light and hence take extra time to figure out the figures or objects that are seen.

You may also be facing a similar situation in the event of your suffering from cataract problem and all these are related to your inability to fixate your sight caused due to loss of cone type cells in your eyes.

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