It seems that there is a correlation like this. When I meditate and pass energy through the nasal passage, and the forehead and inside the head vibrate or energy flows through, I can see a corresponding light even with my eyes closed.

In classical yoga texts and various books, it is often described as "a light like a dazzling sun." In my case, I don't feel dazzled just because I see light, but I simply feel a light of a corresponding intensity, so I don't know if it's exactly the same as that description, but it might just be a difference in expression, and it could be the same thing.

In some books, it is described that light appears when the chakras open, and it seems to be a temporary phenomenon. In my case, I see light when energy flows through my forehead, which is a correlation, and it doesn't seem that my chakras are fully open yet, so perhaps it becomes a more intense light when they open. Even if not, I can see a faint, corresponding light.

Some schools of thought also state that light appears during meditation. In those teachings, it is said that this light is not of great significance, so it should not be worried about or ignored.

In other meditation teachings, light is said to be "tan-ko" (inner light).

In some teachings of yoga, it is said that light emanates from the ajna chakra, allowing one to see things extrasensorially and astrally.

There are various mentions, some of which consider the light to be significant and others that do not. In my understanding, it is like this:

Light is the extrasensory vision itself, as the ajna chakra. It is the light for astral vision. When an energetic pathway (nadi in yoga) is created and opened from the forehead to the center of the head, the ajna chakra and pineal gland, light appears. Some people may have it somewhat open from the beginning, so they may see a corresponding light when they close their eyes. If that light becomes stronger, it may open extrasensory vision even when the eyes are open. Alternatively, even with the eyes open, that vision may appear outside the field of view. Therefore, when trying to see something extrasensorially, moving the eyes widely outward makes it easier to use the extrasensory vision outside the normal field of view. However, in reality, the physical eye and the extrasensory eye are different, so once you get used to it, you don't need to move the physical eyes.

According to the writings of Professor Honzan, seeing strong light means that it is in the "karana" (causal) realm. Even in the astral realm, which is one step before the karana realm, there is a corresponding light, but dazzling light is said to be from the karana realm. The light or color of the astral realm is said to be black in the lower astral realm and light purple in the upper astral realm. Another description says that the upper astral realm is a pitch-black color mixed with light. In any case, the astral realm seems to have the characteristic of being dark.

And, the astral realm is, in essence, a world of emotions, and it contains joy, anger, sorrow, and delight. On the other hand, Karana is a world filled with purity and light. Even in Karana, one is not yet enlightened, but it is still closer to purity than the astral realm.

The light of Karana can be perceived by Ajna when it receives energy.