CONVERGENCE INSUFFICIENCY (CI) is a common binocular vision disorder that is often associated with a variety of symptoms, including eyestrain, headaches, blurred vision, diplopia, sleepiness, difficulty concentrating, movement of print while reading, and loss of comprehension after short periods of reading or performing close activities. Various treatments are commonly prescribed, including passive treatment with base-in prism reading glasses and active treatment, such as home-based therapy using pencil pushups (HBPP) alone, home-based therapy using pencil push-ups plus other therapy techniques, office-based vision therapy, and orthoptics. Consensus regarding the most effective treatment is lacking and there are considerable differences among treatments in time and cost. Recent studies that surveyed the ophthalmic community suggest that HBPP is the most commonly prescribed treatment by both ophthalmologists and optometrists for young patients with symptomatic CI.
Active therapies for the treatment of symptomatic CI typically involve the purposeful, controlled manipulation of target blur, vergence demand, and/or target proximity with the aim of normalizing the accommodative and vergence systems and their mutual interactions. The various active treatment approaches for CI differ in their (1) ability to control and manipulate stimulus parameters (eg, vergence and accommodative demand), (2) dosage, (3) mode of administration, and (4) use of motor learning theory and patient feedback. It is unknown, however, whether these differences affect the outcome of treatment.