Effect of Prolonged Monocular Patching on Convergence and Binocular Functions in Patients Undergoing Occlusion Therapy
Main Article Content
Abstract
Background: Amblyopia is a developmental visual disorder associated with reduced best-corrected visual acuity and impaired binocular visual functions, including convergence, fusion, and stereopsis. Although occlusion therapy is widely used to improve visual acuity in the amblyopic eye, its effect on binocular performance requires further clinical evaluation. Objective: To determine the effect of prolonged monocular patching on convergence and binocular visual functions in children undergoing occlusion therapy for unilateral amblyopia. Methods: This quasi-experimental pre–post study included 56 children aged 5–18 years with unilateral amblyopia who received monocular occlusion therapy for at least 4 hours daily for a minimum of six consecutive weeks. Best-corrected visual acuity, near point of convergence, fusion, and stereopsis were assessed before and after therapy using standardized clinical procedures. Data were analyzed using SPSS version 25, and pre- and post-treatment outcomes were compared using paired statistical testing, with p < 0.05 considered significant. Results: Best-corrected visual acuity improved after therapy, while near point of convergence decreased significantly, indicating better convergence ability. Fusion improved from 0.72 to 0.88 (p = 0.02), and stereopsis improved from 1.85 to 1.20 (p = 0.01). Significant improvements were also observed in BCVA and NPC (p < 0.001). Conclusion: Prolonged monocular patching was associated with improved visual acuity, convergence, fusion, and stereopsis in children with unilateral amblyopia
Article Details
Section
This work is licensed under a Creative Commons Attribution 4.0 International License.
How to Cite
References
1. Birch EE. Amblyopia and binocular vision. Prog Retin Eye Res. 2013;33:67-84. doi:10.1016/j.preteyeres.2012.11.001.
2. Levi DM, Knill DC, Bavelier D. Stereopsis and amblyopia: a mini-review. Vision Res. 2015;114:17-30. doi:10.1016/j.visres.2015.01.002.
3. Ciuffreda KJ, Kenyon RV, Stark L. Abnormal saccadic substitution during small-amplitude pursuit tracking in amblyopic eyes. Invest Ophthalmol Vis Sci. 1979;18(5):506-16.
4. Abraham SV. Accommodation in the amblyopic eye. Am J Ophthalmol. 1961;52(2):197-200. doi:10.1016/0002-9394(61)91115-1.
5. Kenyon RV, Ciuffreda KJ, Stark L. Dynamic vergence eye movements in strabismus and amblyopia: asymmetric vergence. Br J Ophthalmol. 1981;65(3):167-76. doi:10.1136/bjo.65.3.167.
6. Li J, Thompson B, Lam CS, Deng D, Chan LY, Maehara G, et al. The role of suppression in amblyopia. Invest Ophthalmol Vis Sci. 2011;52(7):4169-76. doi:10.1167/iovs.11-7233.
7. Levi DM, Klein SA. Spatial localization in normal and amblyopic vision. Vision Res. 1983;23(10):1005-17. doi:10.1016/0042-6989(83)90011-1.
8. Barrett BT, Bradley A, McGraw PV. Understanding the neural basis of amblyopia. Neuroscientist. 2004;10(2):106-17. doi:10.1177/1073858403262153.
9. Kelly KR, Jost RM, De La Cruz A, Birch EE. Slow reading in children with anisometropic amblyopia is associated with fixation instability and increased saccades. J AAPOS. 2017;21(6):447-51.e1. doi:10.1016/j.jaapos.2017.10.001.
10. Raveendran RN, Bobier WR, Thompson B. Binocular vision and fixational eye movements. J Vis. 2019;19(4):9. doi:10.1167/19.4.9.
11. Webber AL. The functional impact of amblyopia. Clin Exp Optom. 2018;101(4):443-50. doi:10.1111/cxo.12663.
12. Animali S, Steinwurzel C, Dardano A, Sancho-Bornez V, Del Prato S, Morrone MC, et al. Effect of fasting on short-term visual plasticity in adult humans. Eur J Neurosci. 2023;57(1):148-62. doi:10.1111/ejn.15873.
13. Anssari N, Vosoughi R, Mullen KT, Mansouri B. Selective colour vision deficits in multiple sclerosis at different temporal stages. Neuroophthalmology. 2020;44(1):16-23. doi:10.1080/01658107.2019.1615960.
14. Bai J, Dong X, He S, Bao M. Monocular deprivation of Fourier phase information boosts the deprived eye’s dominance during interocular competition but not interocular phase combination. Neuroscience. 2017;352:122-30. doi:10.1016/j.neuroscience.2017.03.053.
15. Baldwin AS, Finn AE, Green HM, Gant N, Hess RF. Exercise does not enhance short-term deprivation-induced ocular dominance plasticity: evidence from dichoptic surround suppression. Vision Res. 2022;201:108123. doi:10.1016/j.visres.2022.108123.
16. Bao M, Dong B, Liu L, Engel SA, Jiang Y. The best of both worlds: adaptation during natural tasks produces long-lasting plasticity in perceptual ocular dominance. Psychol Sci. 2018;29(1):14-33. doi:10.1177/0956797617728126.
17. Kraus CL, Culican SM. New advances in amblyopia therapy I: binocular therapies and pharmacologic augmentation. Br J Ophthalmol. 2018;102(11):1492-6. doi:10.1136/bjophthalmol-2018-312172.
18. Žiak P, Holm A, Halička J, Mojžiš P, Piñero DP. Amblyopia treatment of adults with dichoptic training using the virtual reality Oculus Rift head mounted display: preliminary results. BMC Ophthalmol. 2017;17(1):105. doi:10.1186/s12886-017-0501-8.
19. West S, Williams C. Amblyopia. BMJ Clin Evid. 2011;2011:0709.
20. Pediatric Eye Disease Investigator Group, Wallace DK, Lazar EL, Holmes JM, Repka MX, Cotter SA, et al. A randomized trial of increasing patching for amblyopia. Ophthalmology. 2013;120(11):2270-7. doi:10.1016/j.ophtha.2013.04.008.