25 + 2 — Flickering lights in vision??

HN
I have my glucose test coming up on the 27th. Until then.. I understand your eyes are messed with greatly during pregnancy (my first), but what exactly is messed with? 
This week, there have been two incidents where my vision is distorted by "flickering lights" for about 10-20 minutes at a time. It's as if I looked straight into a light; but it doesn't go away as quickly as it would if that were the case. This favors my right peripheral.
I know everybody is different and every body reacts to pregnancy differently.. but is this something that can be common? I eat well and GD does not run in my family. 
Women who have experienced something like this is preferred. If you have not experienced this, then please mention that when you comment. 
Thank you!