What biotechnology can be used to treat lazy eye, and possibly cure lazy eye? I tried very hard researching and finding the root cause of amblyopia. It is mainly because of imbalance in eye muscle. But, there are a lot more complicated causes of this disease. Thus, I need some help in finding a biotechnology for treating lazy eye.

In order to treat amblyopia you first have to treat the initial problem with the eyes that caused it, which is a medical issue and probably not what you are asking anyway. However, as wikipedia states, "after the underlying cause is fixed, vision is not restored right away, as the mechanism also involves the brain."

As a rule of thumb anything related to brain functions (in humans) is so complex that we don't really have the (bio)technology to just cure it. Sure, their are some advancements in a few areas, but especially if you want biotechnology to do this, you'll probably have to wait at least 10+ years for a medically save and readily usable method.