Scary Visual Symptom

I was just reading something, and when I looked up, could see strange jagged shining lights in the peripheral vision of both eyes which moved and glittered but remained in there, the shape was curved but jagged up and down like something cut with pinking shears. This would not go away so started to panic but could not find anything on the internet. After about ten minutes it began to go away. Getting old is not a barrel of laughs. Was wearing my bifocal specs today. I wonder if they are having some awful, hopefully temporary, effect on my vision. Must give them up.