I went to eye doctor because i had photopsia. he found nothing wrong but i worry about having a brain tumor. what does photopsia caused by brain tumor look like?

Don't panic: May be something as simple as a migraine or indeed something more serious. If you are worried about a brain tumor, speak with your regular doctor.

An eye doctor is you: Eye doctor is your best source to answer this question. Unless you have headaches or any neurological symptoms, it is unlikely that your eye problem is due to a brain tumor. If the eye problem persists or gets worse you need to go see your doctor again and ask him this question.