Do you suddenly lose half of your vision? (Homonymous Hemianopia) Let's talk about this!

Imagine that while you are walking down the street or watching TV, you suddenly lose half of your field of vision, either the right or left side. Or you see one side blurred and black. This can be a very frightening experience. This is what we call Homonymous Hemianopia (or Homonymous Hemianopsia). Don't worry, today we will talk in detail about why this happens, what it means, and what we should do in such a situation.

What is Homonymous Hemianopia?

Simply put, this means that half of the vision is lost on the same side of both eyes (right or left) . "Homonymous" means "on the same side of both." "Hemianopia" means "loss of half of the vision."

Many people here think that this is a problem with the eyes. But actually, this is not a disease of the eyes. This is a problem related to the brain .

Let's see how it works. The things we see with our eyes, that is, visual information, travel through nerves to the brain. Think of the messages coming from our eyes as two roads. These two roads meet at a point in the brain. We call it the ``Optic Chiasm''. At this junction, the right-side vision coming from the right eye, the right-side vision coming from the left eye, goes to the left side of the brain. And the left-side vision goes to the right side of the brain. It's like they cross.

In the case of Homonymous Hemianopia, the problem is not in the eyes, but in the pathways that these messages travel through the brain, after the ``Optic Chiasm''. When one side of the brain is damaged, we lose vision in the part of the visual pathway corresponding to that side. That is why we lose vision on the same side in both eyes.

What are the main reasons for this situation?

Homonymous Hemianopia is not a disease, but a symptom. This means that it is caused by another underlying medical condition. In many cases, it is a sign of a very serious, life-threatening emergency .

See the table below. These are the three most common reasons.

Are there other reasons?

Yes, in addition to these serious conditions, this symptom can also occur due to other reasons.

• Brain tumors - These can be cancerous or benign tumors.
• Head injuries (Traumatic Brain Injuries - TBIs)
• Infections or swelling of the brain, for example `(Encephalitis)`.
• Migraines, especially for those with ``Migraines with auras''.
• Seizures and Epilepsy.
• Diseases of the nervous system such as multiple sclerosis (MS).
• Metabolic problems such as hypoglycemia, which is when blood sugar levels are too low.
• Degenerative diseases of the brain, such as `Creutzfeldt-Jakob disease (CJD)` or `Alzheimer's disease`.

Should I see a doctor immediately?

If you have never had this before, it is very likely that this is a sign of a stroke or a brain hemorrhage . In such cases, time is of the essence. Even a second too late in starting treatment can cause more damage to the brain.

So, if you or someone you know suddenly loses one aspect of their vision like this, the best thing to do is:

• Call an ambulance immediately and go to a hospital.
• Go to the hospital's Emergency Treatment Unit (ETU) .
• Never drive alone at this time of day. It is very dangerous for you and for others on the road.

If you have had a migraine in the past, talk to your doctor about what to do if it happens again. However, if you have any doubts, it is safest to seek medical advice immediately.

How is this treated?

Treatment depends entirely on the cause of this symptom. The first thing your doctor will do is find out what is causing this for you.

• In the case of an ischemic stroke or TIA: Treatment involves restoring blood supply to the brain with thrombolytic drugs or procedures such as thrombectomy.
• If there is bleeding in the brain: Surgery such as a craniectomy may be required to relieve pressure in the skull.
• If you have migraines or epilepsy: The medications prescribed to control those diseases can also control this symptom.
• If it is a brain tumor: You will need to undergo appropriate treatment (surgery, radiation therapy, etc.).

But remember, only your doctor can decide what treatment is right for you. Don't self-treat based on what you find online.

If this continues, how will I manage?

Sometimes, this vision problem can be permanent due to brain damage. It can be a bit challenging, but there are ways to adapt to it and make everyday tasks easier.

Ways to make reading easier

• When reading a book, use something like a ruler to avoid skipping lines.
• Instead of reading a book or newspaper horizontally, try turning it 45 or 90 degrees and reading it vertically. If you can't see the right side, read from top to bottom. If you can't see the left side, read from bottom to top.

Things that help with daily tasks

• When walking, practice turning your head a little more to the side and paying attention to things that are out of your sight. When you go to a new place, stop in one place, turn your head, scan your surroundings, and create a mental picture.
• When walking down the street, have your companion walk on the side that is out of sight, and hold on to his or her hand.
• In a place like a movie theater, sit in a seat that is on the side that you can't see. That way, most of the screen is on the side that you can see.
• You can improve your eye scanning skills by doing things like word search puzzles.
• Talk to your doctor and see if you can add prisms to your glasses. These can help widen your field of vision a bit.
• Driving can be dangerous for many people with this condition. Be sure to talk to your doctor about whether you can drive.

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