A simple yet I guess visible thing happening mostly with highly myopic and glaucomatous eyes, but also with mildly-moderately and even emmetropic.
Let’s describe its appearance in chronological perspective.
At first, there would or could be light reflex near blind spot while moving the eye.
Then, probably some strange feeling has to set in. Like your field of view is darkened a bit. Not easy to guess, but perhaps would be apparent when one eye is closed.
The next, your blind spot seem to be enlarged.
But science is still not clear whether it’s an actual loss of photoreceptors, or rather stretching of eye sclera and deviation of optic nerve placement.
So that even might not be a retinal damage (to which there is zero chance of spontaneous reversal and treatment isn’t ready yet although it will be at the time blindness will be reversible), but stretching and rupture of retina to optic nerve connection, and if eye gets shorter, the blind zone could shrink.
There is blind spot in every normal eye, it is visible at lateral gaze with one eye closed.
You might want to write out whether you’ve found blind spot in yourself and it does not or does arise a suspicion of it being enlarged a bit or more.