When heavenly angels are present with the revived, they do not leave them; they love each one. But if our soul is such that we can no longer enjoy the company of heavenly angels, we long to get away from them, at which point spiritual angels arrive and give us the gift of light. Until then, we do not have the use of our our sight, only of our thoughts.
I was shown how these angels do their work. They seemed to roll a kind of membrane off my left eye toward the nasal septum yo open my eye and give it the use of the light. To the person being revived this seems to be exactly what is happening, but it is only an appearance.
When this small membrane seems to have been rolled off, a dim kind of glow can be seen, like the light seen through the eyelids on waking. We are in a peaceful state, still protected by the heavenly angels.
Next there appears a shadowy something the color of the sky, with a tiny star in it; but I sensed that different people experience this differently.
Afterward something seems to be rolled gently off the face, and we return to consciousness. The angels take the greatest care at this point to prevent any idea from rising out of us unless it is a fairly gentle, loving one. Now we learn that we are a spirit.
from Secrets of Heaven, Volume 1, Sections 182-185