Convergence Insufficiency Treatment Study (CITS)

Convergence insufficiency (CI) is a common and distinct binocular vision disorder that affects approximately 4% of school age children and adults in the United States. Convergence insufficiency is often associated with symptoms such as frequent loss of place while reading, loss of concentration, having to re-read, reading slowly, poor comprehension, sleepiness, blurred vision, diplopia, headaches, and/or eyestrain. A recently completed randomized clinical trial, the Convergence Insufficiency Treatment Trial (CITT), demonstrated that a 12-week program of office-based vergence/ accommodative therapy with home reinforcement was more effective than home-based near target pencil push-ups, home-based computer accommodative therapy plus pencil push-ups, or office-based placebo therapy in treating the symptoms and signs associated with symptomatic CI in children 9 to 17 years of age.

While the home-based therapies in the CITT were not as effective as office-based vergence/accommodative therapy there was some improvement noted. Currently, many eye care professionals only offer home-based therapy, while others suggest passive treatment with base-in prism. At a Pediatric Eye Disease Investigator Group (PEDIG) meeting (Tampa, January 2009), the results of a poll of attendees indicated that a large majority of pediatric ophthalmologists continue to recommend home-based near target push-ups as the initial treatment approach for children with symptomatic CI in spite of the CITT results.

There are significant differences in contact time, complexity, and cost between office-based and home-based therapy for CI. Many clinicians believe that the less costly and less complex treatment option should be attempted first. Although home-based therapy using computer software is becoming more popular, no prospective data are available to demonstrate the effectiveness of home-based vision therapy using computer software compared to home-based near target push-ups or home-based placebo computer therapy. A prospective clinical trial is therefore needed to determine the effectiveness of home-based computer therapy for symptomatic CI compared to traditional home-based near target push-ups and placebo treatment.

The current study is a multi-center randomized clinical trial to evaluate the effectiveness of home-based computer vergence/accommodative therapy and home-based near target push-ups in children 9 to <18 years of age with symptomatic CI.

Inclusion criteria

• Age: 9 to <18 years
• Patient has access to a computer with a CD/DVD drive and internet access for the next 12 weeks
• Best-corrected visual acuity of ≥20/25 in each eye at distance and near
• Exophoria at near at least 4 pd greater than at distance
• Reduced positive fusional convergence at near (<20 pd or fails Sheard's criterion that the PFV measures less than twice the magnitude of the near phoria). PFV is recorded as the prism magnitude where vision is first blurred (or break if no blur is reported).
• Near point of convergence of ≥6 cm break
• Randot Preschool stereoacuity of at least 400 seconds of arc
• CI Symptom Survey score ≥16
• No use of a plus add for near or base-in prism for at least 2 weeks preceding enrollment
• Patient must be wearing appropriate refractive correction (spectacle or contact lenses) for at least 2 weeks prior to enrollment if refractive error is present (based on a cycloplegic refraction within the last 6 months) that meets the following:

• Myopia more than -0.75D spherical equivalent (SE) in either eye
• Hyperopia more than +2.00D SE in either eye
• SE anisometropia >1.00D
• Astigmatism > 1.00D or > 1.50D of meridional difference in either eye Refractive correction for patients meeting the above refractive error criteria must meet the following guidelines:
• SE anisometropia must be within 0.25D of the full anisometropic correction.
• Astigmatism cylinder must be within 0.50D of full correction and axis must be within 5 degrees.
• For hyperopia, the spherical component can be reduced by up to 1.50D at investigator discretion provided the reduction is symmetrical and results in residual (i.e., uncorrected) SE hyperopia that does not exceed +2.00D.
• For myopia, the SE must be within 0.25D of the full myopic correction.
• Parent and patient understand the protocol and are willing to accept randomization.
• Parent has home phone (or access to phone) and is willing to be contacted by Jaeb Center staff.
• Relocation outside of area of an active PEDIG site within the next 15 months is not anticipated.

Exclusion criteria

• ≥2 logMAR line difference in best-corrected visual acuity between the two eyes
• Constant or intermittent exotropia at distance; constant exotropia at near
• Any esotropia at distance or near
• Distance exophoria > 10 pd
• History of strabismus surgery
• Anisometropia ≥2.00D in any meridian between the eyes
• Prior intraocular or refractive surgery
• Primary vertical heterophoria greater than 1 pd
• Diseases known to affect accommodation, vergence, and ocular motility such as multiple sclerosis, Graves orbitopathy, myasthenia gravis, diabetes mellitus, or Parkinson disease
• Current use of any ocular or systemic medication known to affect accommodation or vergence such as anti-anxiety agents (e.g., Librium or Valium), anti-arrhythmic agents (e.g., Cifenline, Cibenzoline), anti- cholinergics (e.g., Motion sickness patch (scopolamine), bladder spasmolytic drugs (e.g., Propiverine), hydroxychloroquine, chloroquine, phenothiazines (e.g., Compazine, Mellaril, Thorazine), tricyclic antidepressants (e.g., Elavil, Nortriptyline, Tofranil)
• Near point of accommodation >20 cm in the right eye
• Manifest or latent nystagmus evident clinically
• History of chronic headaches unrelated to reading activity
• Active symptomatic allergic conjunctivitis
• Developmental disability, mental retardation, attention deficit hyperactivity disorder (ADHD), or learning disability diagnosis that in the investigator's discretion would interfere with treatment or evaluation
• Household member or sibling already enrolled in the CITS OR previously enrolled in the CITT
• Household member is an eye professional, ophthalmic technician, ophthalmology or optometry resident, orthoptist, or optometry student, or employed in an eye care setting
• Acquired brain injury
• Previous office- or home-based vision therapy, orthoptics, home-based near- target push-ups, pencil push-ups, or home-based computer therapy