What is the natural remedies for deep horizontal line wrinkle between the eyes or nasion area?

The muscle responsible for this is the nasalis. The classic image of this happens when someone is squinting their eyes while trying to see small print when reading.

Since this is a muscle,the best natural remedy is to retrain it. The less natural method would be to poison it into inactivity by injecting botox, which is what you are most likely trying to avoid.

The natural method would involve a body and mind approach, because the muscle is only responding to commands from the nervous system. So, if you massage it, that will relieve the physical component, and then address the neurological behavior, which is most likely a recurrent habitual attitude towards something.

You can massage it by gently placing your index fingers in the deepest hollow between your eyes and then, in unison, make small gentle circles as you focus on your breathing and relaxing as much as possible.

The mental part may, or may not, be as much fun. The question I would ask is, "What is it that you are trying to see more clearly?" Think about that, meditate on that, pray on that, and be open to the answer which will naturally come to you when you are ready to receive it.

Then, when the mind and the body have both been reunited in a more harmonious and balanced relationship, your wrinkle should be less noticeable.