I suffered something similar, just once, about twenty years ago, in high school, and never since. Although, instead of an impression of nothingness, it felt more like a Photoshop content aware fill, similar to the optic nerve blind spot, but moved to the fovea.
I was walking the hall to my first period, mainly looking at the bland floor tiles, and didn't realize anything was abnormal. When I happened to look up at the faces of fellow students, I noticed they had no faces, just skin colored smoothness. My hands, and text on the posters on the walls appeared in my peripheral vision, but as soon as I looked directly at anything, it seemed to disappear into an average of it's surrounding colors. I didn't freak out, but calmly walked to my first period, where I was scheduled to take a test. I made way to my desk, and marveled at this oddness, but didn't say anything, until the test was passed out and I could tell it was a page of text, but, of course, the words disappeared upon inspection. I was really impressed how useless my peripheral vision was in dealing with text or faces.
I had an awkward conversation with the teacher, who I feared thought I'd invented a disorder to get out of the test, before being allowed to visit the nurse.
The condition lasted maybe an hour. The ophthalmologist I saw shortly after found nothing wrong with my retinas or eye pressure, and declared it a visual migraine and let me go, with a newfound empathy for those with macular degeneration.
The content-aware fill is what I get as well -- I have some permanent blind areas in my right eye due to optic nerve damage; I lost a lot of peripheral vision, but also the normal optic nerve blind spot is quite a bit larger in that eye -- about 1/4 of the height of my visual field, and half as wide -- fortunately still not affecting the central point of focus.
Obviously no black patch or anything like that; I first noticed the missing section (before I had visual field tests done to detect it properly) while driving, stopped at a light; I rubbed my other eye momentarily, and the traffic light vanished.
I also suffered something similar on multiple occassions in my late 20s and early 30s - growing rainbow zig-zags accompanied by graduals loss of vision in both the center of my field of view and edges of my peripheral vision, although never to the point of total blindness. Incidents would last between one and two hours. But, after several ophatmologist and visits to other physicians, I finally found the trigger: it happened roughly 18 hours after consuming 2 or more glasses of absinthe. Stopped drinking absinthe, haven't had an aura in years.
I was walking the hall to my first period, mainly looking at the bland floor tiles, and didn't realize anything was abnormal. When I happened to look up at the faces of fellow students, I noticed they had no faces, just skin colored smoothness. My hands, and text on the posters on the walls appeared in my peripheral vision, but as soon as I looked directly at anything, it seemed to disappear into an average of it's surrounding colors. I didn't freak out, but calmly walked to my first period, where I was scheduled to take a test. I made way to my desk, and marveled at this oddness, but didn't say anything, until the test was passed out and I could tell it was a page of text, but, of course, the words disappeared upon inspection. I was really impressed how useless my peripheral vision was in dealing with text or faces.
I had an awkward conversation with the teacher, who I feared thought I'd invented a disorder to get out of the test, before being allowed to visit the nurse.
The condition lasted maybe an hour. The ophthalmologist I saw shortly after found nothing wrong with my retinas or eye pressure, and declared it a visual migraine and let me go, with a newfound empathy for those with macular degeneration.