It's not something I've measured, but rather a feeling. Specifically, the blockage in the back of my right eye seems to have cleared, and I feel that the right side has slightly expanded outwards.

Recently, there have been cracking and creaking sounds in the center of my head and the upper half of my head, as if they are loosening. However, it's not just the sounds or the cracking; sometimes, there's a clear sensation, although it's a small feeling, and along with that sensation, my head loosens, expands outwards, and becomes more relaxed overall. Although it's a very small sensation, the feeling in my head is quite different, and I feel that tensions that I hadn't consciously noticed before are being released, leading to deeper relaxation, and that my mind becomes more active. It also seems to make it slightly easier to achieve samadhi (a state of meditative absorption), and that the state of oneness becomes (slightly) easier to maintain.

It's not just affecting my body, but also my mind deeply.

Although the center and upper half of my head are not completely relaxed yet, I feel that the loosening is gradually progressing. I'm experiencing this steady change every day, even though it's a small step at a time.

Usually, when I start meditating, there are cracking and popping sounds almost immediately, but sometimes, after about an hour or two, subtle but steady changes occur.

Also, there are times when changes occur while I'm falling asleep, as if my head is loosening and steady changes are happening.

I think that the changes that occur while sleeping are probably due to the fact that I'm meditating. I don't think there would be much change if I were just sleeping. The changes that I consciously experience mainly occur during seated meditation, while the changes that occur while sleeping are only slight. However, I think that both have the potential for change.