Amblyopia/Lazy Eye is a vision problem that affects both children and adults. This neurodevelopmental loss of vision, typically in one eye, begins in childhood and causes loss of eyesight, poor or no depth perception and many other problems including poor eye hand coordination and reduced reading speed and fluency.
The cause of Amblyopia is clearly understood from decades of research to be a failure in binocular vision (both eyes working together), known as Suppression, that begins in infancy or early toddler-hood, normally due to strabismus (crossed or turned eye), known as Strabismic Amblyopia and/or refractive imbalance, known as Refractive Amblyopia or deprivation caused by congenital cataracts. But, regardless of cause, Amblyopia impacts the lives of all of those who suffer with it at all ages.
The reason for the emphasis of focus on children historically has been because the standard treatment for Amblyopia, occlusion therapy (patching) has been determined to be effective up until approximately age 10. In fact, this is true when you look at the clinical trials that evaluate the efficacy of occlusion as the treatment. However, what new research shows is that age is not a barrier to treatment for Amblyopia when the patient, even an adult patient, is participating in visually interesting techniques that are engaging and designed to decrease the suppression and “turn-on” the function of both eyes working together. This method of turning on both eyes working is known as binocular vision therapy.
Even though occlusion therapy has a host of negative side effects it is routinely prescribed because the volume of clinical research shows visual acuity can improve in young childhood. But, what about the impact of patching on suppression? And does treating the problem of vision loss due to the origin of the amblyopia by “attacking” the suppression from a binocular vision therapy model work better than patching, regardless of age?
The answer to these questions and many more are addressed in a new paper, published in Frontiers in Neuroscience, January 2020, Volume 13, entitled: Patching and Suppression in Amblyopia: One Mechanism or Two?, authors: Yiya Chen, Zhifen He, Yu Mao, Hao Chen, Jiawei Zhou and Robert F. Hess.
The authors conducted a clinical trial to study the following:
- The effect of occlusion therapy on patients’ visual acuity
- The effect of occlusion therapy on patients’ suppression
- The relationship between changes in visual acuity and suppression.
What the researchers concluded was that their findings were consistent with other studies regarding visual acuity and occlusion therapy. That is about 50% of patients’ visual acuity improved with occlusion therapy. But, they also concluded that even in those who had improved in visual acuity from occlusion therapy, the problem with suppression did not change significantly. Therefore, those who did occlusion therapy still had a failure in binocular vision.
The authors further stated, “The notion that monocular occlusion therapy and binocular therapy might involve different neural mechanisms is in line with several other notable differences between the effects of these two therapeutic approaches.”
Now the reader may wonder, what does any of this have to do with adults with Amblyopia? The answer to this question can be found on page 8 of their paper. The authors went on to summarize, based on their own research and that of multiple other cited studies the following five conclusions:
- Occlusion therapy is only effective in children, but ineffective in adults. However, binocular vision therapy has been shown to be effective in adults and children with similar effectiveness.
- Better binocular outcomes have been achieved through binocular vision therapy than occlusion.
- The treatment duration is approximately 3-6 times faster with binocular vision therapy vs occlusion.
- The recurrence rate of amblyopia is high with occlusion but low with binocular vision therapy.
- Studies that have examined children who failed to improve in visual acuity after occlusion therapy actually showed improvement in their visual acuity after binocular vision therapy.
Given the fact that binocular vision therapy has been shown in research to be more effective at the cause of amblyopia, ie suppression, than occlusion therapy and given that binocular vision therapy is effective both in adults and children with similar effectiveness, plus is 3-6 times faster than occlusion therapy, what might we expect if the quality of the binocular vision therapy is advanced into a highly stimulative, visually engaging and enjoyable experience?
This is discussed extensively in our chapter published in the August 2018 3rd Volume, Issue 1 of Advances in Ophthalmology and Optometry entitled: Vision Therapy and Virtual Reality Applications, Drs. Fortenbacher, Bartolini, Dornbos, Tran where we present the latest developments in technology coupling the clinical research in neuroscience and brain neuroplasticity. This modern frontier of new therapeutic applications of highly motivating, patient-engaging binocular vision therapy brings into the next generation, even for adult patients, effective treatment for amblyopia with properly prescribed and supervised virtual reality (VR) in vision therapy.
Now bringing this into practical applications, for the last 5 years we have provided office-based vision therapy, utilizing Vivid Vision Virtual Reality as an integral element for our adult patients with amblyopia treatment with excellent outcomes. Our patients have gained dramatically improved depth perception, as well as visual acuity.
What’s more, during the last 2 years, we have dispensed home Vivid VR as a new addition to our at-home vision therapy regimen used in conjunction with our doctor and vision therapist guided office-based vision therapy sessions. In the home units, the patient can use their VR equipment anywhere they have access to WiFi where they literally toggle into our office computer, working on the same VR programs, just as if they were physically in our office.
The advantages of these new technologies in vision rehabilitation and vision therapy have positioned adult patients, just as much as children, to now obtain effective treatment for their Amblyopia.
Dan L. Fortenbacher, O.D., FCOVD