Non-invasive Brain Stimulation for Treating Symptomatic Convergence Insufficiency (NIBSCI)

A Randomized Controlled Study Using Non-invasive Brain Stimulation to Facilitate the Effectiveness of Vergence/Accommodative Therapy in Symptomatic Convergence Insufficiency

The goal of this randomized controlled trial is to test the effectiveness of non-invasive brain stimulation in treating adults with symptomatic convergence insufficiency compared to vergence/accommodative therapy. The main questions it aims to answer are:

1. Can non-invasive brain stimulation shorten the treatment time of office-based vergence/accommodative therapy for convergence insufficiency?
2. Is non-invasive brain stimulation alone just as effective as office-based vergence/accommodative therapy in treating convergence insufficiency?

The investigators hypothesize that non-invasive brain stimulation will shorten the treatment time from 12 weeks to 8 weeks of office-based vergence/accommodative therapy and that non-invasive brain stimulation alone would be equally effective as office-based vergence/accommodative therapy in improving symptomatic convergence insufficiency.

Participants will be randomized into one of three treatment groups:

1. Non-invasive brain stimulation with office-based vergence/accommodative therapy.
2. Sham stimulation with office-based vergence/accommodative therapy.
3. Non-invasive brain stimulation only.

Researchers will compare baseline measurements of near point of convergence (NPC) and positive fusional vergence (PFV) to post-treatment measurements for each group.

Study Overview

• Status: Recruiting
• Conditions: Convergence Insufficiency
• Intervention / Treatment: Behavioral: Office-Based Vergence/Accommodative Therapy; Device: Anodal-Transcranial Direct Current Stimulation; Device: Sham Transcranial Direct Current Stimulation

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Arijit Chakraborty, PhD; Phone Number: 630-960-3172; Email: achakr@midwestern.edu
• Study Contact Backup: Name: Adrienne C Quan, OD; Phone Number: 630-960-3183; Email: aquan@midwestern.edu

Study Locations

• United States
  • Illinois
    • Downers Grove, Illinois, United States, 60515
      • Recruiting
      • Midwestern University Eye Institute
      • Contact: Sherri Olsen; Phone Number: 630-515-7368; Email: solsen@midwestern.edu
      • Principal Investigator: Arijit Chakraborty, PhD
      • Sub-Investigator: Adrienne C Quan, OD
      • Sub-Investigator: Clinton R Prestwich, OD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Best-corrected visual acuity of > 20/25 in each eye at distance and near
• Exophoria at near at least 4∆ greater than at far
• Receded near point of convergence of > 6 cm break
• Insufficient positive fusional vergence at near (< 15∆ base-out blur or break)
• CISS score of 16 and greater for children or 21 and greater for adults
• Have had a dilated fundus examination within the last 12 months
• Informed consent and willingness to participate in the study and be randomized

Exclusion Criteria:

• Previously treated for convergence insufficiency with home- or office-based vergence/accommodative therapy
• Amblyopia (> 2-line difference in best-corrected visual acuity between the two eyes)
• Constant strabismus
• History of strabismus surgery
• Convergence insufficiency secondary to acquired brain injury or neurological disorder
• Manifest or latent nystagmus
• Systemic disease known to affect accommodation, vergence, and ocular motility including multiple sclerosis, Graves disease, myasthenia gravis, Parkinson's disease, cerebral palsy, and diabetes
• Developmental disability, attention deficit hyperactivity disorder (ADHD), learning disability or cognitive dysfunction that would interfere with treatment
• Taking medications that can affect normal neurological function including antipsychotics, antiepileptics, and opioids
• Presence of metal or electronic implants in or on the body, including pacemakers

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: NIBS-OBVAT; 8 sessions of non-invasive brain stimulation with 8 weeks of office-based vergence/accommodative therapy.	Behavioral: Office-Based Vergence/Accommodative Therapy; Office-based vergence accommodative therapy involves weekly in-office appointments with the therapist lasting approximately 60 minutes per visit during which time in-office procedures will be performed, and home therapy procedures will be demonstrated. Participants will be prescribed 15 minutes of home reinforcement therapy procedures to be completed 5 days per week. Therapy will consist of two phases adapted from the Convergence Insufficiency Treatment Trial (CITT). Therapy procedures will include gross convergence, accommodation. non-computer based vergence, and computer-based vergence.; Other Names: OBVAT; Orthoptic training; Device: Anodal-Transcranial Direct Current Stimulation; Non-invasive brain stimulation will involve the use of anodal transcranial direct current stimulation to apply a 2 milliamp current over the left frontal eye field for approximately 20 minutes with a ramp up to the maximum programmed current and ramp down of 20 seconds.; Other Names: tDCS; a-tDCS
Active Comparator: NIBS; 8 sessions of non-invasive brain stimulation only.	Device: Anodal-Transcranial Direct Current Stimulation; Non-invasive brain stimulation will involve the use of anodal transcranial direct current stimulation to apply a 2 milliamp current over the left frontal eye field for approximately 20 minutes with a ramp up to the maximum programmed current and ramp down of 20 seconds.; Other Names: tDCS; a-tDCS
Sham Comparator: OBVAT; 8 sessions of sham stimulation with 8 weeks of office-based vergence/accommodative therapy.	Behavioral: Office-Based Vergence/Accommodative Therapy; Office-based vergence accommodative therapy involves weekly in-office appointments with the therapist lasting approximately 60 minutes per visit during which time in-office procedures will be performed, and home therapy procedures will be demonstrated. Participants will be prescribed 15 minutes of home reinforcement therapy procedures to be completed 5 days per week. Therapy will consist of two phases adapted from the Convergence Insufficiency Treatment Trial (CITT). Therapy procedures will include gross convergence, accommodation. non-computer based vergence, and computer-based vergence.; Other Names: OBVAT; Orthoptic training; Device: Sham Transcranial Direct Current Stimulation; Sham transcranial direct current stimulation will be applied over the left frontal eye field with the current ramping up for 20 seconds before ramping down for 20 seconds. The 2 milliamp current stimulation will occur for only a few seconds at the start and at the end of the 20 minutes.; Other Names: Sham tDCS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Near Point of Convergence (NPC)	A change in the NPC break and recovery values measured in centimeters (cm) from baseline after treatment.	4 weeks, 6 weeks, and 8 weeks during treatment; 6 months and 12 months post-treatment
Positive Fusional Vergence (PFV)	A change in the near PFV blur, break, and recovery values measured in prism diopters (∆) from baseline after treatment.	4 weeks, 6 weeks, and 8 weeks during treatment; 6 months and 12 months post-treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Convergence Insufficiency Symptoms Survey (CISS)	A change in the CISS score from baseline after treatment. The minimum score is 0 and the maximum score is 60. Lower scores indicate a better outcome.	8 weeks during treatment; 6 months and 12 months post-treatment

Collaborators and Investigators

• Sponsor: Midwestern University
• Collaborators: Southern California College of Optometry at Marshall B. Ketchum University; New Jersey Institute of Technology; Pennsylvania College of Optometry; University of Waterloo School of Optometry and Vision Science

Publications and helpful links

General Publications

• Scheiman M, Kulp MT, Cotter SA, Lawrenson JG, Wang L, Li T. Interventions for convergence insufficiency: a network meta-analysis. Cochrane Database Syst Rev. 2020 Dec 2;12(12):CD006768. doi: 10.1002/14651858.CD006768.pub3.
• Alvarez TL, Scheiman M, Santos EM, Yaramothu C, d'Antonio-Bertagnolli JV. Convergence Insufficiency Neuro-mechanism in Adult Population Study Randomized Clinical Trial: Clinical Outcome Results. Optom Vis Sci. 2020 Dec;97(12):1061-1069. doi: 10.1097/OPX.0000000000001606.
• Convergence Insufficiency Treatment Trial Study Group. Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol. 2008 Oct;126(10):1336-49. doi: 10.1001/archopht.126.10.1336.

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2024
• Primary Completion (Estimated): December 31, 2028
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: May 17, 2023
• First Submitted That Met QC Criteria: May 17, 2023
• First Posted (Actual): May 26, 2023

Study Record Updates

• Last Update Posted (Estimated): April 26, 2024
• Last Update Submitted That Met QC Criteria: April 25, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Transcranial Direct Current Stimulation; Non-invasive Brain Stimulation; Convergence Insufficiency; Office-Based Vergence/Accommodative Therapy; Frontal Eye Fields
• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; Eye Diseases; Cranial Nerve Diseases; Strabismus; Ocular Motility Disorders
• Other Study ID Numbers: CIRB-IL 22013

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes