I have an on call nurse service which I called. She said I should call 911. The nurse said do some vision tests like hand mom something to reach for & how many fingers test. First mom said couldn't see but did the same a while later and she could reach for the bottle & knew how many fingers. Nurse said I should advise doctor what happened in the morning.
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.
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.
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.