Should we know exactly about the optic nerve that powers our vision?

How do you read this article? How do you see the beautiful things in the world around you, the faces of your loved ones? Behind all this is an amazing connection between our eyes and our brain. The main one that builds that connection, that works like a 'data cable', is the optic nerve, or optic nerve . Let's talk about this simply today.

What exactly is the Optic Nerve?

Simply put, the optic nerve is a bundle of millions of nerve fibers, like a cable made up of many electrical wires. These nerves start behind our eyes and connect directly to our brain.

This is the easiest way to imagine how this works.

• Your eye is like a camera.
• The retina, at the back of the eye, is like the sensor in this camera. It detects light and converts what we see into electrical signals.
• The optic nerve is like the cable that connects the camera and the computer. That is, the electrical signals generated in the retina are carried to the 'computer' called the brain through this optic nerve.

This is the second of the 12 cranial nerves that are directly connected to our brain. But this one is a little different from the other nerves. Because, it is considered part of our Central Nervous System (CNS) , that is, the brain and spinal cord. The other cranial nerves belong to the Peripheral Nervous System (PNS) .

Where is this optic nerve located?

The journey of these two nerves, which start behind your eyes and travel to your brain, is a bit complicated. The journey basically goes like this:

1. Optic Canal: First, this nerve enters our skull through a small tunnel made of bone called the optic canal.

2. Optic Chiasm: Once inside the skull, there is a Y-shaped junction where the nerves from the two eyes meet. Here something amazing happens. Some of the nerve fibers from the right eye are switched to the left, and some of the nerve fibers from the left eye are switched to the right.

3. Brain: After this junction, the nerve fibers travel directly to the visual cortex , an area at the back of the brain. This is where we interpret and analyze what we see as "pictures." This nerve transfer is what allows us to combine the images from both eyes into a single, clear 3D image.

Are there other functions besides vision?

Yes, absolutely. On the way to the brain, a small portion of these nerve fibers branch out to other places. These are mainly important for things like:

• Pupil Reflexes: Imagine that when you suddenly go into bright sunlight, the pupil of your eyes automatically shrinks. And when you go into a dark room, it enlarges. This happens to control the amount of light entering the eye. Since this process has to happen very quickly, the signals for it are sent by those dividing nerve fibers.
• Accommodation Reflex: When you look at a book in front of you and then suddenly look at a tree in the distance, the tree becomes clearer. This is because the shape of the lens inside the eye changes, allowing it to focus on both distant and near objects. The optic nerve is also involved in controlling this process.
• Circadian Rhythm: Simply put, this is our body's 'biological clock'. This clock controls when we go to sleep, when we wake up, and how our body temperature and blood pressure change at different times of the day. Information about light that travels to the brain through the optic nerve helps this clock distinguish between day and night.

What are the conditions that affect the optic nerve?

Unfortunately, there are several medical conditions that can damage this valuable nerve. Some of them are listed in the table below.

Common symptoms of an optic nerve problem

When there is a problem with the optic nerve, various symptoms can occur. These can be temporary or permanent.

Some of the commonly seen symptoms are:

• Blurred vision.
• Difficulty recognizing colors or seeing colors differently.
• Seeing black spots or gaps in the field of vision (Blind Spots) .
• Eye pain, especially when moving the eyes.
• Seeing two things at once (Double Vision / Diplopia) .
• Seeing flashes of light before the eyes (Photopsias) .
• Decreased peripheral vision.
• Sudden decrease or complete loss of vision.

How can we protect our optic nerve?

There are many things we can do to protect this precious nerve and our vision.

• Get regular eye exams: Even if you don't need to wear glasses, getting your eyes checked at least once a year can help detect diseases like glaucoma early.
• Maintain a healthy weight: Controlling body weight is beneficial for overall health as well as for the eyes.
• Eat a balanced diet: Eat foods that contain vitamins (especially B vitamins) and minerals (e.g. copper) that are essential for healthy nerves.
• Control other diseases: If you have diseases like diabetes or high blood pressure , it is very important to control them well according to your doctor's instructions . These diseases can cause serious damage to the eyes and optic nerve.
• Avoid smoking: Smoking and the use of other tobacco products damage the delicate blood vessels that supply blood to the optic nerve.
• Protect your eyes and head: Wear helmets and safety goggles when playing sports, using machinery, and riding bicycles.

When should I see a doctor?

If you notice any gradual changes in your vision, eye pain, or blurred vision, see your doctor or an ophthalmologist as soon as possible.

However, if you experience a sudden change in vision or loss of vision, do not ignore it. It could be a medical emergency. Go to the nearest hospital's Emergency Department (ETU) immediately.

This amazing connection between our eyes and our brain, the optic nerve, is something we often overlook. But keeping this nerve healthy is essential for us to enjoy the beauty of our lives. If you have any concerns about your vision, never hesitate to talk to a doctor about it.

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