Has this happend to any of you? My mom with dementia all of a sudden said she “can't see everything is black”.

My thoughts are that it could have been a TIA.
When doctors see someone who is old and has dementia they often aren't willing to investigate beyond that - who knows, perhaps at this point in her life they are right.

I agree, call 911 first in any emergency.

My godmother had ALZ and was blind but she had macular degeneration.

I have only heard of sudden blindness once. It was really odd. My aunt had a horrible pregnancy and delivery.

She went blind for four days in the hospital during delivery. I don’t know what caused her blindness. She had all kinds of medical issues and even died in her 40’s.

She had rheumatoid arthritis, kidney failure, went into a coma from doctor prescribing the wrong medication at the wrong dosage. Was just a tragedy all around.

You wrote that "she cud (sic) reach for the bottle."   Is she an alchoholic?  I don't intend to be rude or critical, but if she couldn't see b/c of an alcohol related issue, EMS should have been called.    Different issues and treatment are involved for visual disturbances  and those arising from alcohol.

But it's over, and it's not my intent to criticize you, just emphasize the fact that EMS should be involved in situations like visual blackout.

Does she get regular eye exams, and has her doctor diagnosed any medical issues with her eyes?   I hope you're taking her to at least a PCP tomorrow.

To be honest, if it were me, I would have called 911 immediately. I would not be posting on an anonymous site where no one can really do anything including give you a diagnoses of what’s going on. It’s a good sign that she could see again, but since you don’t know why this happened, you really should have called 911.