Occasionally, one eye appears larger than the other on my 77 year old Mom. Is it a symptom of something going on?

Sounds brain-related to me - is she also getting TIAs or anything like that? I'd get it checked out soonest.

I would suggest you to consult doctor at Killeen Vision Source instead of self diagnosing it.

On the doctor shows, that's a sign of a brain problem. If it comes and goes, maybe you could wait until morning, but do call or visit the doctor then.

This is a question for a doctor. If I noticed one of my mother's pupils was blown, I would take her to the ER.