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Your Child Has a Lazy Eye, You Aren’t Lazy to Catch A Vision Therapist, Are You? Better Late Than Never

by | May 1, 2023 | Manuscripts | 0 comments

Ms. Roshni Majumder, B. Optom

M. Optometry Student, Amity University, Haryana, India

 

The showstopper: Neuroplasticity and adult amblyopia

Amblyopia is usually referred to as poor vision due to abnormal neural alteration in early life, deprivation of pattern vision or abnormal interaction of binocular functions. (1) It is no more arguable that vision continues to mature well even after the first year of life. (2,3) The ability of the brain to alter and adapt to changes significantly is referred to as neuroplasticity. When visual input to the brain is compromised during the early “critical” or “sensitive phases” of enhanced neuroplasticity, amblyopia develops as a result of structural and functional changes in the neural systems. Amblyopia in adults usually goes untreated because of the notion that the adult brain lacks the neuroplasticity to retrain how to receive visual information. Early in the twenty-first century, it became clear that this hypothesis was false. Several treatments that can enhance neuroplasticity in the mature visual cortex have been found to be effective in amblyopia animal models, and human clinical trials are now being conducted with similar approaches. A recent report has demonstrated that increasing spatial and temporal contrast sensitivity is linked to an improvement in important visual functions, which may be assessed by increased visual acuity. (4)  Visual plasticity refers to the visual system’s capacity to modify its responses in response to variations in the visual input. (5)

What works on adult amblyopia?

Recent evidence suggests that making use of dichoptic training, perceptual learning, and video gaming lead to improvements in adult amblyopia. Conventional therapies do act as an icing on the cake (Table 1). Also, tools like bar readers combined with anaglyphs and multimodality approach to manage amblyopes does totally steal the show in today’s management strategies where we train multiple visual functions at a time by using different methods (Figure 1). It is said we see with our brain, as long as our brain can adapt to new changes (neuro and visual plasticity) amblyopia can be managed by a vision therapist irrespective of age.

Figure 1: Tools for anti-suppression
(Flowchart prepared by the author)

 

Conclusions

Parents of amblyopic children are often misled by the fact that amblyopia or lazy eye can be managed only during the early years of life, which definitely is an old school misnomer. Evidence suggests amblyopes might show improvements in vision, stereopsis and overall binocularity when treated with customised vision therapy. And this miracle is made possible by the miraculous contributions of the vision therapist or orthoptist.

Table 1: Techniques used in management of adult amblyopia

S. No Technique/tool Mechanism
1. Dichoptic stimulation (6) When stimuli of varying contrast are provided to each eye, the urge to combine both the information leads to improvement in binocularity and reduction of suppression
2. Perceptual learning (7,8) Plasticity is induced by perceptual learning in the normal visual system
3. Video games (9,10) Video games to induce plasticity and improve visual function in adult amblyopia.
4. Conventional therapies (11) Conventional therapies provide a forced choice to visualize through the amblyopic eye

 

References:

  1. Von Noorden G, Campos E. St Louis: Mosby. Binocular Vision and Ocular Motility. 2002. 246–286 p.
  2. Canfield RL, Smith EG, Brezsnyak MP, Snow KL, Aslin RN, Haith MM, et al. Information Processing Through the First Year of Life: A Longitudinal Study Using the Visual Expectation Paradigm. Monographs of the Society for Research in Child Development. 1997;62(2):i.
  3. Siu C, Murphy K. The development of human visual cortex and clinical implications. Eye and Brain. 2018 Apr;Volume 10:25–36.
  4. Polat U. Perceptual learning induces neuroplasticity, enabling improvement of visual functions. Expert Review of Ophthalmology. 2009 Dec 9;4(6):573–6.
  5. Zhou J, Liu Z, Clavagnier S, Reynaud A, Hou F. Visual Plasticity in Adults. Neural Plast. 2017;2017:8469580. doi:10.1155/2017/8469580
  6. Hess RF, Mansouri B, Thompson B. A new binocular approach to the treatment of Amblyopia in adults well beyond the critical period of visual development. Restorative Neurology and Neuroscience. 2010;28(6):793–802.
  7. Levi DM, Li RW. Improving the performance of the amblyopic visual system. Philosophical Transactions of the Royal Society B: Biological Sciences. 2009 Feb 12;364(1515):399–407.
  8. Polat U, Ma-Naim T, Belkin M, Sagi D. Improving vision in adult amblyopia by perceptual learning. Proceedings of the National Academy of Sciences. 2004 Apr 27;101(17):6692–7.
  9. Li RW, Ngo C, Nguyen J, Levi DM. Video-Game Play Induces Plasticity in the Visual System of Adults with Amblyopia. PLoS Biology. 2011 Aug 30;9(8):e1001135.
  10. To L, Thompson B, Blum JR, Maehara G, Hess RF, Cooperstock JR. A Game Platform for Treatment of Amblyopia. IEEE Transactions on Neural Systems and Rehabilitation Engineering. 2011 Jun;19(3):280–9.
  11. Kishimoto F, Fujii C, Shira Y, Hasebe K, Hamasaki I, Ohtsuki H. Outcome of conventional treatment for adult amblyopia. Japanese Journal of Ophthalmology. 2014 Jan 26;58(1):26–32.

Cover image depicting an anti-suppression test in the clinic, image captured and modified for publication by the Author.

**Declaration of no conflict of interest: This blog is written solely for education purpose, and it does not have any financial support and conflict of interest**

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