After having my thyroid removed, and now taking synthroid (thyroxine).......how does graves disease cont to effect me?

Antibodies: Even people who've been ablated for grave's disease remain at some risk for exophthalmos. Smoking is a particularly well known risk. I've seen a few adults who developed this condition as long as 25 years following ablation (1 smoked). Though clearly the risk is smaller once thyroid is long ablated, this eye problem can also occur during ablation process.

Remnant thyroid: In addition to the eye changes, thyroidectomy often does not remove all of the thyroid tissue, and the persistence of the auto-antibodies can cause recurrent thyrotoxicosis. But if you are on synthroid (thyroxine) with normal thyroid blood levels, this is not the case.

Still at risk: You will always be at a small risk for eye and other problems secondary to graves' disease, but the risk is small and declines with time. There is no way to predict or prevent problems except to continue to keep your thyroid level normal.