Meditation Experience?

[onacloudynight]

Hey everyone, so I've recently had a phenomenon come up during meditation and was wondering what could be going on. 

I've been meditating consistently for 5 months now and recently have started the "do nothing" technique, with my eyes open. During the first minute or two, my vision will start to flicker and will fade in and out. My vision does this constantly throughout the meditation and about 10 minutes after I'm finished. One day this week I meditated throughout the day and it lasted the whole day, regardless of what I was doing. 

Anyway I was just curious to find out if anyone has any idea what this could be? Is it just another experience that will past with time? Or could it be some neurological problem?