A Randomized Trial of Base-in Prism Reading Glasses Convergence Insufficiency in Children

Inclusion Criteria: Age: 9 to <19 years. Best corrected visual acuity of ≥20/25 in each eye at distance and near Willingness to wear eyeglasses or contact lenses to correct refractive error, if necessary Willingness to wear glasses for reading and other near work Exophoria at near at least 4 greater than at far Insufficient positive fusional convergence (fails Sheard's criterion) Receded near point of convergence of  6 cm break Random dot stereopsis appreciation using a 500 seconds of arc target. CI Symptom Survey score  16 Exclusion Criteria: Amblyopia (> 2 line difference in best corrected visual acuity between the two eyes). Constant strabismus History of strabismus surgery. Anisometropia  2D in any meridian between the eyes. Prior refractive surgery. Vertical heterophoria greater than 1 . Systemic diseases known to affect accommodation, vergence and ocular motility such as: multiple sclerosis, Graves thyroid disease, myasthenia gravis, diabetes, Parkinson disease. Any ocular or systemic medication known to affect accommodation or vergence (Anti-anxiety agents (Librium or Valium), Anti-arrhythmic agents (Cifenline or Cibenzoline), Anticholinergics (Motion sickness patch (scopolamine), Bladder spasmolytic drugs (Propiverine), Chloroquine, Phenothiazines (Compazine, Mellaril, or Thorazine), Tricyclic antidepressants (Elavil, Nortriptyline, or Tofranil) Accommodative amplitude <5 D in either eye as measured by the Donder's push-up method. Manifest or latent nystagmus. Developmental disability, mental retardation, attention deficit hyperactivity disorder (ADHD), or learning disability diagnosis in children that in the investigator's discretion would interfere with treatment. Household member or sibling already enrolled in the BI-CITT. Any eye care professional, ophthalmic technician, ophthalmology or optometry resident or optometry student.