This used to happen to me in all of my pregnancies, along with leg cramps. I was told it was just one of those things and nothing could be done, which was of no help. In my 4th pregnancy, I was seen by my primary care physician for a nagging cough and she recognized signs of a heart issue and sent me to the ER, where they measured by calcium, magnesium and potassium. I was critically low in all of those (causing an arrhythmia) and had to be supplemented with all and re-tested before being released.
Once those levels were normal, the eye twitching and leg cramps went away and stayed away for the remainder of my pregnancy. Looking back, I was probably deficient in at least one of those throughout my prior pregnancies but it was never tested by my OB-GYN. My 4th pregnancy was twins so that's probably what pushed it to a risky level where in prior pregnancies it was just annoying.
So...my recommendation would be to see if you can have these levels tested, or ask if it's OK for you to supplement. In general, supplementing with magnesium, calcium and increasing your potassium levels with food or OTC supplements is no big deal but with pregnancy, you want to be sure you have your doc's OK first. For eye twitching, the culprit is usually low magnesium or potassium, or both. There are foods that are high in both of these, but if your levels are really low, taking a supplement can help boost the levels back to normal fast and then you can maintain with foods.
Hope that helps point you in the right direction!