Hi A
Treatment for convergence insufficiency generally involves a combination of in -clinic computer program exercises (where available) and exercises you can do at home, such as stereograms and convergence cards. Some people also do 'pencil push ups' although the efficacy of this can be less predictable. Prisms can help in those people who have not benefited from other treatment methods.
However, going by what you describe you may have other problems besides convergence insufficiency. Specifically, you may have issues with your spectacle power/refractive error and in general, it would be good to have a comprehensive eye examination to make sure there is no other eye condition causing your problems.
I would suggest seeing an ophthalmologist/eye doctor, or if you have already seen one, to consider a second opinion for a thorough eye check.
