Answer transcribed from Brightway's Interview with Dr. Bryce Appelbaum: 

Convergence insufficiency is so common and by the language used, you would think that means can't cross my eyes, which in my opinion is absolutely not what convergence insufficiency is. Convergence insufficiency is kind of a spatial mismatch in that converging happens when we are either looking something up close or something's approaching us. It's a binocular coordination problem where again, our eyes are pointing at a different place in where the target is, which is allowing the images not to fuse. It's addressed on a brain basis to raise to somebody's awareness where their eyes are pointing or how they're taking in that space. You can eliminate that mismatch but rarely does it have something to do with eye muscle strength or length

The old school treatment modalities for convergence insufficiency is something called pencil push-ups, which literally is look at a pencil, watch it as it comes in, and do this a thousand times. Then all of a sudden, you're gonna strengthen the system and the problem will be gone. I think for most people, that's going to be not too exciting, very repetitive, and learning won't take place in that setup. Rarely have I ever heard of pencil push-ups working.

There are certain spectacle lenses that can be made where you can use a prism, which basically moves the world in this case from midline outward a little so that the eyes don't have to converge as much. Those only really are helpful for certain profiles. You always want to be careful that that type of image displacement doesn't create a new normal where we need a stronger amount of power to create the same effect because we're kind of adapting that prism. That often happens, where it's great to not see things double anymore but then you need something stronger just to maintain that same level of clarity and the same image displacement. Nonetheless, that can be effective for some people. Sometimes just having the right prescription magnifying lens, which helps the brain not have to over-focus the eyes as much, can help engage the periphery. By engaging the periphery, it’s easier for the eyes to line straight ahead. That can be effective in making things more comfortable, at least with reading and computer work

From a vision therapy standpoint, if convergence insufficiency is the only diagnosis, though it’s almost never the case, that's a slam dunk for vision therapy. It just comes down to teaching the individual where to look and how to use the internal and external muscles of the eyes to provide the right feedback. Then if the brain is in fact rewired, as long as there's no new head injuries or new visual stress that we don't have the tools in place to meet the demands of what’s been rewired, convergence insufficiency is just a label that essentially goes away because it no longer applies. Also with brain injuries, we know that very busy visual environments can create a lot of symptoms and a sensitivity of motion of being too aware of the periphery, a lot of times convergence insufficiency can just be a matter of as simple as the sounds not knowing where to look. If we can learn where to look, then again that label is just a temporary endpoint that doesn't apply anymore.