Lazy eye, or amblyopia as it is called by doctors
, is caused when both eyes don't send the same information to the brain. When the brain tries to "unscramble" the information, the confusion is so great that it decides to stick with just one image of the two. When just one eye is being used to generate all of the visual information, the other eye becomes non-functional. After too long in this state, the condition is irreversible, and the brain stops recognizing input from the "bad" eye at all. This obviously has significant consequences, such as difficulty with three dimensional vision.
The good news is that the vision loss and "lazy eye" are completely correctable, which is why vision screening is done before kids even start school. The bad news is that, unless it's addressed early, it might be too late to make any significant age. For most people, the best time to correct lazy eye is while they are still in elementary school (or, even better, preschool). Depending on the reason for the amblyopia, the correction involves wearing glasses or having surgery
(whatever is needed to make the eyes see and send the same image to the brain).
The best option at this point would be to follow up with an ophthalmologist
as soon as possible, to see if there is something that can be done.