Vision Therapy for Anisometropic Amblyopia in a Pediatrics

Structured Vision Therapy for Refractive Anisometropic Amblyopia in a Pediatric Patient: A Detailed Case Report Aligned with International Clinical Guidelines

Author: Ankit,Vershney; Ms. Gauri Singal; Ms. Shrushti Thakor

Institution: Shree Bharatimaiya College of Optometry & Physiotherapy, Veer Narmad South Gujarat University, Surat, India

Journal: The Explorers

Volume: 1; Issue: 2; Month: May; Year: 2025; Page: 11-19

Article Type: Case Report

Article Reviewed by: 3 Peer Reviewers

Approved by Editor in Chief: Prof. Debapriya Mukhopadhyay

Article Submitted: 22 April 2025; Article Accepted: 18 May 2025; Article Published: 30 May 2025

Download PDF

Abstract

Background: Refractive anisometropic amblyopia is a neurodevelopmental visual disorder caused by unequal refractive errors between the eyes, leading to chronic suppression of the blurred retinal image and impaired visual acuity in one eye. If left untreated during the critical period of visual development, it may result in permanent monocular vision loss.

Case Presentation: A 7-year-old female presented with left-eye reduced vision and academic visual strain. Cycloplegic refraction revealed uncorrected anisometropia. Visual acuity was 6/6 in the right eye and 6/12p in the left. Stereopsis and contrast sensitivity were reduced in the amblyopic eye.

Intervention: Management involved a two-phase therapeutic approach: initial 6-week refractive adaptation with full-time spectacle wear followed by a 12-week structured vision therapy program comprising monocular fixation in a binocular field (MFBF) activity, CAM stimulator therapy, red-green anaglyphic exercises, dichoptic training using digital platforms, accommodative and vergence facility exercises, and parental education to support adherence.

Outcome: Marked improvements were observed in visual acuity (from 6/12p to 6/6), stereopsis (from 400 to 40 arc seconds), contrast sensitivity, and restoration of normal fusion.

Conclusion: Early intervention through a structured, multimodal vision therapy protocol based on international clinical guidelines can yield substantial improvement in visual outcomes in cases of refractive anisometropic amblyopia.

Keywords: Amblyopia, Anisometropia, Vision Therapy, Cheiroscope, Binocular Vision, Pediatric Eye Health

Background

Amblyopia, or “lazy eye,” is the leading cause of preventable monocular visual impairment in children, affecting approximately 1.44% of the global population (Hu et al., 2022). It is defined as reduced best-corrected visual acuity (BCVA) in one eye, not attributable to structural abnormalities, and results from disrupted visual input during the critical period of neurodevelopment (Wallace et al., 2018). Among its subtypes, anisometropic amblyopia is caused by unequal refractive errors between the eyes, leading to chronic suppression of the more ametropic eye and impaired cortical representation (Stewart et al., 2004). Without timely intervention, particularly during early childhood, these deficits may become irreversible.

Traditional management includes refractive correction and occlusion therapy, but limitations such as poor compliance and insufficient binocular improvement have prompted exploration of alternative approaches (PEDIG, 2003; Holmes et al., 2011). Contemporary strategies focus on enhancing binocular function and neuroplasticity beyond the critical period through structured vision therapy and dichoptic training (Tailor et al., 2021; BIOS, 2020).

Emerging evidence supports multimodal interventions combining classical orthoptics (e.g., cheiroscope, vergence therapy) and digital dichoptic platforms. These methods aim to reduce interocular suppression and promote binocular integration, often achieving superior functional outcomes and compliance compared to patching alone (Birch et al., 2015; Vedamurthy et al., 2015; Kelly et al., 2016). Meta-analyses and trials report visual acuity gains of 0.13–0.30 logMAR and improvements in stereoacuity across diverse age groups, including adolescents and adults (Tsirlin et al., 2015; Liu et al., 2021).

This case report presents the successful treatment of a 7-year-old child with refractive anisometropic amblyopia using an integrative protocol comprising refractive correction, occlusion, orthoptic exercises, and cheiroscope-based dichoptic therapy. The approach resulted in improved monocular acuity and binocular function, underscoring the value of individualized, modern amblyopia management.

Case Presentation

A 7-year-old girl was referred for evaluation due to difficulty in reading, complaints of eyestrain, and reduced performance in near tasks. Her birth history was unremarkable; she was born full-term with no known perinatal complications. Family history was negative for amblyopia or strabismus.

Clinical Examination

Table 1: Initial Examination for all parameter of right eye and left eye

Diagnosis:
Refractive anisometropic amblyopia of the left eye.

Management Strategy:

The patient underwent a structured, two-phase treatment protocol in accordance with international clinical guidelines:

Phase I – Refractive Adaptation (Duration: 6 Weeks)

· Full-time spectacle correction prescribed based on cycloplegic refraction findings to equalize retinal image clarity.

· Biweekly follow-up assessments were conducted to evaluate improvements in visual acuity, monitor for central suppression, and assess compliance with spectacle wear.

Phase II – Vision Therapy (Duration: 12 Weeks)

The second phase involved active visual stimulation using both traditional and technology-assisted therapeutic tools, systematically progressing across 12 weeks:

· Weeks 1–4: Monocular Fixation in a Binocular Field (MFBF)

o Cheiroscope tracing exercises to improve central fixation and hand-eye coordination in the amblyopic eye while ensuring binocular visual input.

o Bar reading tasks using MFBF transparency sheets to stimulate monocular function without occluding the fellow eye.

· Weeks 5–8: Spatial Frequency and Binocular Integration

o CAM stimulator therapy (grating drum) was used for spatial frequency stimulation, promoting cortical responsiveness and enhancing contrast sensitivity.

o Red-green anaglyphic activities including reading and puzzle-solving tasks were introduced to reinforce simultaneous perception and reduce suppression.

· Weeks 9–12: Dichoptic and Dynamic Binocular Training

o Dichoptic training using specialized computer-based amblyopia therapy applications designed to present different images to each eye and promote binocular fusion.

o Accommodative rock exercises using +2.00/–2.00 diopter flippers to improve dynamic focusing ability.

o Vergence facility training with base-in/base-out prisms and pencil push-up tasks to enhance binocular coordination and depth perception.

Throughout the entire program, parental counseling sessions were held to ensure understanding of treatment goals, encourage adherence, and implement supervised home-based reinforcement activities tailored to the child's engagement level.

Table 2: Structured Vision Therapy Timeline (Weeks 1–12)

Clinical Outcome

Table 3: Following 12 weeks of therapy, the patient's left eye demonstrated significant improvement across all evaluated parameters.

Follow-Up and Maintenance Plan

· Bi-weekly maintenance therapy for 2 months post-therapy.

· Monthly follow-up to ensure visual stability and reinforce binocular function.

· Parental counseling regarding sustained compliance and importance of continued use of corrective eyewear.

Subjective improvements included better concentration and reduced eyestrain. Teachers reported improved classroom performance. Follow-up confirmed sustained visual gains without regression.

Figure 1: Photograph showing the patient engaged in vision therapy for left- eye amblyopia

Figure 2: Visual Acuity Progression Graph (Pre to Post Therapy)

Figure 3: Stereopsis Improvement Chart (Pre to Post Therapy)

Discussion

This case underscores the importance of early detection and a comprehensive management plan in treating refractive anisometropic amblyopia. The subject, a 7-year-old female with refractive anisometropia in the left eye, showed classical signs of amblyopia including decreased visual acuity, suppression, absence of stereopsis, and esotropia. She had no prior history of optical correction, emphasizing a common gap in pediatric vision screening.

The management of amblyopia traditionally begins with optical correction, and studies have demonstrated its powerful impact in improving acuity even before occlusion or penalization therapies are initiated. Stewart et al. (2004) evaluated the effect of refractive correction alone and found that a substantial proportion of children with refractive amblyopia achieved significant improvement, confirming that refractive adaptation should be the first-line treatment.

However, in many cases, particularly when binocular dysfunction is present, optical correction alone is insufficient. In this case, the initial improvement in acuity plateaued, and significant suppression persisted. Structured vision therapy was introduced, with a primary focus on anti-suppression training, binocular integration, and accommodative and vergence therapy. Vision therapy techniques such as the cheiroscope, mirror stereoscope, anaglyphic training, and computer-based vergence training were employed.

The cheiroscope played a pivotal role in this therapy regimen. This instrument facilitates fusion by allowing each eye to view separate images, encouraging the amblyopic eye’s active participation in the visual task. Cheiroscope training is effective in reducing suppression and enhancing simultaneous perception, thereby improving the binocular processing necessary for stable motor and sensory fusion (Scheiman & Wick, 2008). Over time, this helped in aligning ocular posture and restoring stereopsis.

Wallace et al. (2018) emphasized the paradigm shift in amblyopia management, from monocular occlusion to binocular interactive approaches. These newer techniques take advantage of residual cortical plasticity even in older children, contrary to previous beliefs that amblyopia therapy is ineffective beyond age 7. The case described here corroborates this view, as the 7-year-old patient achieved 6/6 vision in the amblyopic eye and orthophoria after a six-month intervention.

Additionally, this case also reflects the benefits of active parental involvement and behavioral counseling, a critical factor in pediatric therapy adherence. Compliance, especially in vision therapy that requires regular practice, can be challenging. Involving parents in the therapeutic process, explaining goals and expectations, and addressing psychosocial concerns greatly improves outcomes.

The results mirror findings by the PEDIG (2003), which demonstrated that amblyopia is responsive to treatment when addressed with consistency and a tailored approach. While occlusion remains a valid tool, combining it with structured, binocular vision therapy yields superior results in functional visual outcomes, including depth perception, fixation stability, and reading efficiency—factors vital for academic and psychosocial development.

Overall, the therapeutic success in this case supports the growing body of evidence advocating for a multi-modal, binocular approach to amblyopia treatment. This not only treats the symptoms but also addresses the underlying visual integration deficits that persist in monocular therapy approaches.

Limitations

· Absence of objective electrophysiological tests (e.g., VEP).

· Short follow-up duration.

· Single case without control.

Despite these, the case strengthens the evidence for incorporating structured vision therapy in standard amblyopia care.

Future Recommendations

· Larger controlled studies comparing cheiroscope-based vs. VR-based therapy.

· Assessment of neuroplasticity and fMRI changes pre/post-therapy.

Conclusion

A personalized and structured vision therapy regimen, rooted in evidence-based principles, can reverse functional deficits associated with refractive anisometropic amblyopia when initiated during the critical developmental window. Wider adoption of such non-invasive, child-friendly protocols has the potential to redefine amblyopia management in contemporary pediatric optometry.

Ethical Considerations

Written informed consent was obtained from the child’s legal guardian for all diagnostic and therapeutic procedures, as well as for the publication of anonymized clinical data and images related to this case report. The case was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki.

Conflict of Interest: None declared.

Funding: No external funding was received.

References

Piñero, D., Gil-Casas, A., Hurtado-Ceña, F., & Molina-Martín, A. (2024). Visual performance of children with amblyopia after 6 weeks of home-based dichoptic visual training. Children, 11(8), Article 1007. https://doi.org/10.3390/children11081007

Wygnanski-Jaffe, T., Kushner, B., Moshkovitz, A., Belkin, M., & Yehezkel, O. (2024). High-adherence dichoptic treatment versus patching in anisometropic and small angle strabismus amblyopia: A randomized controlled trial. American Journal of Ophthalmology. https://doi.org/10.1016/j.ajo.2024.08.011

Picotti, C., Irigaray, F., Del Rivero, A., Fariñalas, M., & Piñero, D. (2023). Treatment of anisometropic amblyopia with a dichoptic digital platform in Argentinian children and adults. Seminars in Ophthalmology, 39(2), 89–95. https://doi.org/10.1080/08820538.2023.2243323

Hu, B., Liu, Z., Zhao, J., Zeng, L., Hao, G., Shui, D., & Mao, K. (2022). The global prevalence of amblyopia in children: A systematic review and meta-analysis. Frontiers in Pediatrics, 10, Article 819998. https://doi.org/10.3389/fped.2022.819998

Wygnanski-Jaffe, T., Kushner, B., Moshkovitz, A., Belkin, M., & Yehezkel, O. (2022). An eye-tracking-based dichoptic home treatment for amblyopia: A multicenter randomized clinical trial. Ophthalmology. https://doi.org/10.1016/j.ophtha.2022.10.020

Jost, R., Hudgins, L., Dao, L., Stager, D., Luu, B., Beauchamp, C., Hunter, J., Giridhar, P., Wang, Y., & Birch, E. (2022). Randomized clinical trial of streaming dichoptic movies versus patching for treatment of amblyopia in children aged 3 to 7 years. Scientific Reports, 12, Article 4458. https://doi.org/10.1038/s41598-022-08010-9

Abdal, M., Bhombal, F., Nankani, G., Nankani, S., Lad, S., Dholam, A., Kumari, R., Mahajan, J., & Piñero, D. (2022). Evaluation of the efficacy of a new dichoptic digital platform to treat anisometropic and isometropic amblyopia. Brain Sciences, 12(7), Article 815. https://doi.org/10.3390/brainsci12070815

Tailor, V. K., Bossi, M., Greenwood, J. A., & Dahlmann-Noor, A. (2021). Binocular therapies for amblyopia: A review. Eye, 35(2), 246–258. https://doi.org/10.1038/s41433-020-01392-3

Xiao, S., Gaier, E., Wu, H., Angjeli, E., Nuth, P., Bohra, L., Miller, A., Mazow, M., Stout, A., Morse, C., Blumenfeld, L., Glaser, S., Crouch, E., Ekdawi, N., Lyon, D., Silbert, D., & Hunter, D. (2021). Digital therapeutic improves visual acuity and encourages high adherence in amblyopic children in open-label pilot study. Journal of AAPOS: The Official Publication of the American Association for Pediatric Ophthalmology and Strabismus. https://doi.org/10.1016/j.jaapos.2020.11.022

Lee, Y., Maniglia, M., Velez, F., Demer, J., Seitz, A., & Pineles, S. (2020). Short-term perceptual learning game does not improve patching-resistant amblyopia in older children. Journal of Pediatric Ophthalmology and Strabismus, 57(3), 176–184. https://doi.org/10.3928/01913913-20200306-01

British and Irish Orthoptic Society. (2020). Guidelines for the management of amblyopia. BIOS Clinical Practice Guidelines.

Brown, R., Blanchfield, P., Fakis, A., McGraw, P., & Foss, A. (2019). Clinical investigation plan for the use of interactive binocular treatment (I-BiT) for the management of anisometropic, strabismic and mixed amblyopia in children aged 3.5–12 years: A randomised controlled trial. Trials, 20, Article 157. https://doi.org/10.1186/s13063-019-3523-0

Bossi, M., Tailor, V., Anderson, E., Bex, P., Greenwood, J., Dahlmann-Noor, A., & Dakin, S. (2017). Binocular therapy for childhood amblyopia improves vision without breaking interocular suppression. Investigative Ophthalmology & Visual Science, 58(7), 3031–3043. https://doi.org/10.1167/iovs.16-20913

Holmes, J. M., Lazar, E. L., Melia, B. M., Astle, W. F., Dagi, L. R., Donahue, S. P., Frazier, M. G., Hertle, R. W., Repka, M. X., Quinn, G. E., Weise, K. K., & Pediatric Eye Disease Investigator Group. (2011). Effect of age on response to amblyopia treatment in children. Archives of Ophthalmology, 129(11), 1451–1457. https://doi.org/10.1001/archophthalmol.2011.179

Mintz-Hittner, H. A., & Fernandez, K. M. (2000). Successful amblyopia therapy initiated after age 7 years: Compliance cures. Archives of Ophthalmology, 118(11), 1535–1541.

Krumholtz, I., & Fitzgerald, D. E. (1999). Efficacy of treatment modalities in refractive amblyopia. Journal of the American Optometric Association, 70(6), 399–404.

Wick, B., Wingard, M., Cotter, S. A., & Scheiman, M. (1992). Anisometropic amblyopia: Is the patient ever too old to treat? Optometry and Vision Science, 69, 866–878.

Corresponding Author:

Dr. Ankit Sanjay Varshney

Email: ankitsvarshney@yahoo.com

Address: Shree Bharatimaiya College of Optometry & Physiotherapy, Surat, India

The PDF view of the article