You're right - I get the same thing, I was advised it's due to low magnesium and high calcium levels (hair analysis confirmation) - the CA/Mg ratio, particularly low Mg causes poor muscle response in the eye area. In other words, adrenal fatigue. Insulin issues can also cause the same thing, which is what the CA/Mg ratio also reflects - glucose metabolism. If you can, get a hair analysis done, highly recommend it, it can reveal alot as to what is going on with you chemistry wise.