I really believe my vision problems are thyroid related. Mostly I think due to light intolerance and contact fit. My night vision was steadily worsening (I'm only 34) and repeated trips to my optometrist didn't help. Then I started taking synthroid. The first two weeks on the meds while my body was adjusting I had amazing energy, and I could see better than I could in years. Then my body adjusted and med doses have changed and my vision is okay but night vision is very bad again, I am super-sensitive to light (wasn't before meds), and the contact brand I've worn for years no longer fits comfortably. So, yes, I do think thyroid affects vision.