You say your vision is getting worse, such as? Sensitive to light or blurry vision? If so, it may be be what is called
For that it would be called Nystagmus: Here is an excellent site that explains this along with treatment
Here is a support group for this as well
Hope this helps, If you need anything else please feel free to ask.
The only thing I can suggest you do, is since you are on Thyroid medication is to see an endocrinologist since they deal with the thyroid a lot more in depth than a regular MD.
Hope this helps,