When a child is asked to attend to near point tasks, such as reading or schoolwork, the visual demand naturally increases due to the close proximity of the task. Vision is called upon to converge, accommodate and track. One must converge to keep the image single, accommodate to keep the image clear and then track by moving eyes from “spot-to-spot” i.e. when reading or writing. Of the three tasks, convergence delays, or convergence insufficiency, has been shown to overlap symptoms common with ADHD. Because of the overlap, it is important to include a functional vision examination when sorting out an ADHD diagnosis. In an article published by Strabismus, the relationship between convergence insufficiency and ADHD was explored. The study was a retrospective review of 266 patients that were seen at a pediatric ophthalmology clinic. It was noted that patients diagnosed with ADHD were 3 times more likely to have convergence insufficiency.
General symptoms of a child (or adult) with convergence insufficiency include; difficulty concentrating when performing near work, reduced comprehension when reading, having to re-read passages often in order to remember, eye fatigue, falling asleep while reading, headaches and even double vision. Putting up with these symptoms may be too much and the person suffering from convergence insufficiency may decide the demand is too great, consequently avoiding the near point tasks. Avoidance could be interpreted as fidgeting, difficulty concentrating, etc.
General symptoms of a child (or adult) with ADHD include, fidgeting, difficulty concentrating with near point tasks, difficulty sitting still, difficulty attending to tasks, impulsive behavior or excessive talking or behavior.
Because both conditions have similar symptoms i.e. difficulty concentrating, fidgeting and difficulty attending to tasks, it is worth considering a binocular vision workup. If ultimately the difficulty originates from convergence insufficiency, the prescribed treatment will be shorter and more effective. If convergence insufficiency is contributing to the aforementioned symptoms, treatment consists of in-office optometric vision therapy and in most cases is relatively straight forward.