I've been on Lamictal for about 15 years, and I have had a few times in the past several years when my night vision was really bad, but only for a day or two, then back to normal, with maybe a couple of months in between times. Yesterday my vision during the day was quite blurry. I felt like I was looking through a rainy window or something and I had to keep blinking my eyes to see if it got better. All is well again today, even though I had quite a good size partial seizure this morning.

I haven't really changed the Lamictal dose, so I'm not even sure if it's related to that, but it feels to me that it is at least related to the epilepsy. I suppose the Lamictal could be messing with me, too.
I hope your vision settles down! Good luck with it!