Effects of Brock String Therapy vs Computer Based Vergence Therapy on Reading Speed, Visual Comfort and Binocular Functions in School Aged Children with Convergence Insufficiency
DOI:
https://doi.org/10.68279/hrf55k07Keywords:
Convergence insufficiency; Brock String Therapy; Computer-Based Vergence Therapy; vision therapy; reading speed; visual comfort; binocular visionAbstract
Background: Convergence insufficiency can produce visual discomfort and difficulty during sustained near activities in school-aged children. Brock String Therapy and Computer-Based Vergence Therapy are used to train binocular function, but direct comparative evidence across symptomatic, clinical, and reading outcomes remains limited. Objective: To compare the effects of Brock String Therapy and Computer-Based Vergence Therapy on convergence insufficiency symptoms, visual comfort, binocular functions, and reading speed in school-aged children with convergence insufficiency. Methods: This parallel-group randomized clinical trial included 60 children aged 8–15 years recruited at Government Girls Elementary School Kotla Malam, District Rajanpur. Participants were allocated to Brock String Therapy (n=30) or Computer-Based Vergence Therapy (n=30). Outcomes included the Convergence Insufficiency Symptom Survey (CISS), visual comfort, near point of convergence (NPC), positive fusional vergence (PFV), and reading speed. Paired and independent-samples t-tests were used for within- and between-group comparisons. Results: Both groups demonstrated significant pre-to-post changes across all outcomes (p<0.001). Post-treatment CISS scores were lower with Computer-Based Vergence Therapy than Brock String Therapy (23.07±6.03 vs 29.30±6.37; p<0.001), and reading speed was higher (140.03±10.72 vs 127.13±17.33 WPM; p=0.001). Computer-Based Vergence Therapy also showed more favorable post-treatment visual-comfort, NPC, and PFV values. Conclusion: Both interventions were associated with favourable short-term changes, while Computer-Based Vergence Therapy demonstrated more favourable post-treatment outcomes across the assessed measures.
References
1. Ghasemi Fard F, Mirzaie H, Hosseini SA, Riazi A, Ebadi A. Vision-related tasks in children with visual impairment: a multi-method study. Front Psychol. 2023;14:1180669. doi:10.3389/fpsyg.2023.1180669.
2. Anggini WY, Harmoko DD, Bakhtiar A. Preparing pre-school children with sensorial and practical life class. Res Dev J Educ. 2024;10(2):930-939. doi:10.30998/rdje.v10i2.25217.
3. Stephens-Sarlos E, Stephens P, Szabo A. The efficacy of the sensorimotor training program on sensorimotor development, auditory and visual skills of schoolchildren aged 5–8 years. Child Youth Care Forum. 2025;54:323-352. doi:10.1007/s10566-024-09818-4.
4. Alnawmasi MM, Elmadina AM, Alenezi B, Aldakhil S, Alrasheed SH, Almutairi NM. Near vision symptoms and their association with refractive error and binocular vision function among medical sciences students. PeerJ. 2026;14. doi:10.7717/peerj.21532.
5. Ding J, Ma MY, Lu HH, Backus BT, Levi DM. Recovery of depth perception in adults with abnormal binocular vision. Vision Res. 2026;242:108783. doi:10.1016/j.visres.2026.108783.
6. Mishra A, Dass S, Sharma B, Sharma U. Impact of binocular vision anomalies and stereopsis on individual performance: a comprehensive review of binocular vision disorders. Indian J Exp Biol. 2026;64(3):190-196. doi:10.56042/ijeb.v64i03.25737.
7. Yushan D, Hong Z. Frequency and associated factors of accommodative and non-strabismic binocular vision dysfunctions among clinical adults in Western China: a cross-sectional study. Medicine (Baltimore). 2025;104(34). doi:10.1097/MD.0000000000043881.
8. Almahmoud OH, Mahmmod KM, Mohtaseb SA, Totah NJ, Nijem DFA, Hammoudeh AN. Assessment of digital eye strain and its associated factors among school children in Palestine. BMC Ophthalmol. 2025;25(1):81. doi:10.1186/s12886-025-03919-x.
9. Harrington S, Davison PA, O'Dwyer V. School performance and undetected and untreated visual problems in schoolchildren in Ireland: a population-based cross-sectional study. Ir Educ Stud. 2022;41(2):367-388. doi:10.1080/03323315.2021.1899024.
10. Zahid A. Assessment of binocular vision disorders and their impact on reading performance and learning efficiency. Research Consortium Archive. 2026;4(2):4009-4024. doi:10.5281/zenodo.21992203.
11. Stein J. The visual basis of reading and reading difficulties. Front Neurosci. 2022;16:1004027. doi:10.3389/fnins.2022.1004027.
12. Alrasheed SH, Aldakhil S. Heterophoria, fusional vergence, and near point of convergence in Sudanese hospital-based population. Afr Vis Eye Health. 2024;83(1):869. doi:10.4102/aveh.v83i1.869.
13. Rovick LP. Evaluation and management of convergence insufficiency in adults. J Binocul Vis Ocul Motil. 2022;72(4):234-242. doi:10.1080/2576117X.2022.2114307.
14. Sonum S, Amir A, ul Ain Q, Sanaullah M. Comparative effectiveness of different therapies for convergence insufficiency. Ophthalmol Pak. 2024;14(3):67-72. doi:10.62276/OphthalmolPak.14.03.162.
15. Li S, Tang A, Yang B, Wang J, Liu L. Virtual reality-based vision therapy versus OBVAT in the treatment of convergence insufficiency, accommodative dysfunction: a pilot randomized controlled trial. BMC Ophthalmol. 2022;22(1):182. doi:10.1186/s12886-022-02393-z.
16. Trbovich AM, Zynda AJ, Togashi T, Burley C, Mucha A, Collins MW, et al. Randomized controlled trial of Brock String vision therapy for receded near point of convergence following concussion. J Neurotrauma. 2025;42(19-20):1708-1718. doi:10.1177/089771512513599.
17. Nirghin U. Reading rate of low vision children using optical devices: a pilot study. Afr Vis Eye Health. 2023;82(1):854. doi:10.4102/aveh.v82i1.854.
18. Pang Y, Gabriel H, Tan QQ. Convergence insufficiency symptom survey: a tool to evaluate convergence excess in young adults. Ophthalmic Physiol Opt. 2023;43(4):615-622. doi:10.1111/opo.13106.
19. Hussaindeen JR, Mavroidis M, Ashwin BP, Sruthi MS, Theagarayan B. Near phoria and near point of convergence parameters in children with hearing and speech impairment: a cross-sectional study. Health Sci Rep. 2025;8(7). doi:10.1002/hsr2.70991.
20. Rovira-Gay C, Argiles M, Mestre C, Masdemont-Isern M, Pujol J. Objective evaluation of fusional vergence after a vision therapy protocol in typical binocular vision. Ophthalmic Physiol Opt. 2025;45(5):1173-1185. doi:10.1111/opo.13528.
21. Tekin E, Kurt B, Koçan M, Kaya ES, Unver F. Acute effects of Brock String-based visuo-oculomotor training on postural stability and reactive motor performance in athletes: a pilot study. Sportverletz Sportschaden. 2026. doi:10.1055/a-2914-2145.
22. Coco-Martin MB, Piñero DP, Leal-Vega L, Hernández-Rodríguez CJ, Adiego J, Molina-Martín A, et al. The potential of virtual reality for inducing neuroplasticity in children with amblyopia. J Ophthalmol. 2020;2020:7067846. doi:10.1155/2020/7067846.
23. Chang MY, Morrison DG, Binenbaum G, Heidary G, Trivedi RH, Galvin JA, et al. Home- and office-based vergence and accommodative therapies for treatment of convergence insufficiency in children and young adults: a report by the American Academy of Ophthalmology. Ophthalmology. 2021;128(12):1756-1765. doi:10.1016/j.ophtha.2021.05.017.
24. Jenewein EC, Cotter S, Roberts T, Kulp M, Mitchell GL, Jones-Jordan LA, et al. Vergence/accommodative therapy for symptomatic convergence insufficiency in children: time course of improvements in convergence function. Ophthalmic Physiol Opt. 2023;43(1):105-115. doi:10.1111/opo.13062.
25. Gantz L, Stiebel-Kalish H. Convergence insufficiency: review of clinical diagnostic signs. J Optom. 2022;15(4):256-270. doi:10.1016/j.optom.2021.11.002.
26. CITT-ART Investigator Group. Effect of vergence/accommodative therapy on reading in children with convergence insufficiency: a randomized clinical trial. Optom Vis Sci. 2019;96(11):836-849. doi:10.1097/OPX.0000000000001442.
27. Dos Santos LEPR, Yázigi FG, De Freitas AM, Barros GL, Biasotto-Gonzalez DA, Politti F. Effect of oculomotor therapy on convergence insufficiency and postural control: protocol for a randomized clinical trial. J Adv Med Med Res. 2025;37(9):24-35. doi:10.9734/jammr/2025/v37i95923.
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Copyright (c) 2026 Tehreem khalid, Dr. Aamir Gul Memon, Prof. Dr. Muhammad Naveed Babur, Mahnoor Hafeez, Rabia Riasat, Alishba Khalid, Hadia Arshad (Author)
This work is licensed under a Creative Commons Attribution 4.0 International License.
