Convergence Insufficiency
Conditions
Brief summary
This study is designed to evaluate changes in objective measures of disparity vergence after office-based vergence/accommodative therapy (OBVAT) for convergence insufficiency (CI) in children 12-17 years old.
Detailed description
30 participants with normal binocular vision and 30 with CI will be recruited for this prospective study. All participants with CI will be treated with 12 weeks of office-based vergence/accommodative therapy. The primary outcome measure will be the average peak velocity for 4° symmetrical convergence steps. Other objective outcome measures of disparity vergence will be time to peak velocity, latency, and accuracy. Changes in clinical measures \[near point of convergence (NPC), positive fusional vergence at near (PFV)\] and symptoms will be evaluated.
Interventions
one -to-one treatment by a trained therapists. The subject is asked to perform 5-6 therapy procedures during a 60 minute therapy session. The subject is also asked to perform 15 minutes per day of home-based therapy.
Sponsors
Salus University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Eligible participants received 12 weeks of office vergence/accommodative therapy
Eligibility
Sex/Gender
ALL
Age
9 Years to 17 Years
Healthy volunteers
Yes
Inclusion criteria
* CI Symptom Survey score ≥ 16 * Exophoria at near at least 4 greater than at far * Receded near point of convergence (NPC) of 6 cm break * Insufficient positive fusional vergence (PFV) at near (i.e., failing Sheard's criterion or PFV ≤15 base-out break) * Best-corrected distance visual acuity of 20/25 or better in each eye * Random dot stereopsis appreciation of 500 seconds of arc or better * Wearing appropriate refractive correction (spectacles of contact lenses) for at least 2 weeks prior to final determination of eligibility for any of the following uncorrected refractive errors (based on cycloplegic refraction within prior 12 months) * No use of BI prism or plus add at near for 2 weeks prior to study and for duration of study
Exclusion criteria
* Constant strabismus at distance or near * Esophoria of ≥ 2∆ at distance * Vertical heterophoria ≥ 2∆ at distance or near * ≥ 2 line interocular difference in best-corrected visual acuity * Near point of accommodation \>20 cm in either eye as measured by push-up method * Manifest or latent nystagmus * History of strabismus surgery or refractive surgery * CI associated with head trauma or known disease of the brain * Diseases known to affect accommodation, vergence, or ocular motility * Inability to comprehend and/or perform any study-related test
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in average peak velocity for 4° symmetrical convergence steps after 12 weeks of therapy | After 12 weeks of therapy | The ISCAN RK-826PCI binocular tracking system (Burlington, MA) will be used used to objectively record horizontal vergence eye movements. Five parameters will be measured with this instrument and the primary outcome measures will be the change in average peak velocity for 4° symmetrical convergence steps |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in latency for 4° symmetrical convergence steps after 12 weeks of therapy | After 12 weeks of therapy | The ISCAN RK-826PCI binocular tracking system (Burlington, MA) will be used used to objectively record horizontal vergence eye movements. Five parameters will be measured with this instrument and a secondary outcome measures will be the change in latency for 4° symmetrical convergence steps |
| Change in accuracy for 4° symmetrical convergence steps after 12 weeks of therapy | After 12 weeks of therapy | The ISCAN RK-826PCI binocular tracking system (Burlington, MA) will be used used to objectively record horizontal vergence eye movements. Five parameters will be measured with this instrument and a secondary outcome measures will be the change in accuracy for 4° symmetrical convergence steps |
| Change in time to peak velocity for 4° symmetrical convergence steps after 12 weeks of therapy | After 12 weeks of therapy | The ISCAN RK-826PCI binocular tracking system (Burlington, MA) will be used used to objectively record horizontal vergence eye movements. Five parameters will be measured with this instrument and a secondary outcome measures will be the change in time to peak velocity for 4° symmetrical convergence steps |
| Change in the near point of convergence | After 12 weeks of therapy | The near point of convergence will be measured using the Near Point Rule at baseline and after 12 weeks of therapy. The change in this measurement will a secondary clinical outcome measure. |
| Change in the positive fusional vergence | After 12 weeks of therapy | Positive fusional vergence will be measured using a handheld target placed 40 cm from the participant and using a horizontal prism bar. Positive fusional vergence will be measured at baseline and after 12 weeks of therapy. The change in this measurement will a secondary clinical outcome measure. |
| Change in settling time for 4° symmetrical convergence steps after 12 weeks of therapy | After 12 weeks of therapy | The ISCAN RK-826PCI binocular tracking system (Burlington, MA) will be used used to objectively record horizontal vergence eye movements. Five parameters will be measured with this instrument and a secondary outcome measures will be the change in settling time for 4° symmetrical convergence steps |
Countries
United States
Contacts
Primary ContactMitchell Scheiman, OD, PhD
Outcome results
None listed