Typically you'll notice a persistent black spot in your vision. Particularly if you're looking at a bright field like a blank white page on your monitor.
Cite? My vague understanding of how vision works is that your brain will tend to interpolate over missing data rather than perceive it as black. So you need to actually test whether you can discriminate things in the affected field of view.
I have this spot in my right eye that resembles dead pixels. Just tiny blackness. If I let my eyes try to focus on it, it moves with my eyeball, so then they try to focus on the new location... ad infinitum. So they sort of jitter on a path upwards and to the right. I can only see it in certain lighting.
Eye doctor couldn't see anything wrong with the area and suggested it might be a floater that got attached and would go away on its own within 6mo. That was 4yr ago and it's still around. It's not getting worse so it doesn't bother me, it just reminds me of the saa from the Wheel of Time.
I would have expected interpolation versus vision artifacts as well, but apparently that's an "only sometimes" thing.
You have a speck of gunk in your vitreous near the focal point. Not retina. You can’t ‘see’ damage to your retina… you brain just interpolates.
The gunk in your vitreous can stay there a long time… it’s gel, more or less, and can take a long time to move.
Generally, yes. That's why people tend to go for quite a while before noticing the damage.
The mechanism isn't perfect and there are plenty of scenarios where your brain doesn't fill in the information, like the one I described. You also see it when looking at repeating patterns. It isn't something super obvious and if you choose to ignore it, it mostly goes away.
If your brain magically filled in the missing part of your vision in all cases, ask yourself how we would ever know that anyone has any amount of damage to their vision. Obviously we do know, since people talk about it. There must be some mechanism by which the damage becomes apparent to the patient.
The comment by utensil4778 I am replying to made a generalization and did not mention their personal experience (although the phrasing maybe suggested that their experience was consistent with the general claim).
If I look at a straight line with the right eye, I see a "kink" in it. Grids look like they are warped in near the center.
Turns out, that I have a "pinhole" damaged area in the right eye's fovea. It's small enough that the brain can "interpolate" over it, especially when both eyes can see the object.
Don't know how OP did it, but I've been tested a couple of times at the optometrist by field of view machines*. You concentrate on a central point while the machine shows you a pictogram in a random location with a random timing. You click a button every time you see one.
Note: not an actual name, I don't know how these are called.
