It is fair to say that we have come a long way in terms of addressing amblyopia. Having been discovered early enough in its course the conventional treatment is rather straightforward and effective. Nonetheless, it is also fair to say that when it comes to additional therapy options, we are still a long way from establishing the most effective and standardized protocols. For that, we will guide you through various treatment options which exist, and comment on their efficiency and recommendations from the literature, with an emphasis on active treatment options for amblyopia.
As mentioned in quite a few previous blogs, patching and correct refractive correction remain the pillar of amblyopia treatment. However, a plethora of additional therapy options, some more effective than others, were introduced over the past century. Whereas conventional treatment (i.e. patching) is considered being a “passive” treatment, these additional therapy options are sometimes referred to as “active” treatment options for amblyopia. In today’s blog we shall discuss what those therapies are, and the most effective of them will be described in more detail in later blog posts.
In short, the most popular additional amblyopia therapy options are:
– Perceptual learning
– Binocular dichoptic training
Pleoptic training was introduced in the 1960s in Europe where it was really popular for quite some time. Interestingly though, it never really took off in the US. The main goal of this training is to stimulate the central foveal fixation in those children in whom the fixation in the amblyopic eye is eccentric – not right into the fovea as it should be. After some really promising first studies, the later studies showed that the gain in visual acuity is inferior compared to conventional patching. To make matters worse, this training also requires expensive and specialist gear, which means that it can only be conducted on an outpatient basis in eye clinics or ophthalmology departments. Therefore, except for some particularly specific cases, it is not recommended anymore for the treatment of child amblyopia.
Another intriguing “novelty” in terms of active amblyopia treatment is perceptual learning. Defined as “any relatively permanent and consistent change in the perception of a stimulus array, following practice or experience with this array” by Eleanor Gibson more than 60 years ago, it is the field of vision training that many pieces of research have been devoted to in the last few decades. In more layman terms it is basically a learning process that eventually, due to still somewhat obscured mechanisms, leads to the improvement of vision. The visual stimuli used vary immensely among different approaches of perceptual learning, the most common being a contrast grating stimulus.
The training protocols, namely duration and participants’ inclusion criteria, also vary significantly among these approaches. With the constant development of software and algorithms, the perceptual learning approaches are getting more and more complex, as is the analysis of these visual interventions. That said, we are still far from establishing standardized protocols for the use of perceptual learning in children’s amblyopia treatment. Those approaches then, for the time being, remain mostly reserved for experimental use and are as such not yet widely used in routine clinical practice. It is worth noting, though, that much research shows that improvement of visual function (visual acuity as well as contrast sensitivity) with perceptual learning can not only be possible in children, but also in adults – way beyond the critical period for vision development!
Binocular Dichoptic Training with AmblyoPlay
Next and also the most effective amongst active treatment approaches for amblyopia is near vision activities and binocular dichoptic training. Whilst near vision activities are fundamentally any activities that a child performs with the fellow eye occluded – reading, video games etc. – the more interesting from the biological point of view, and more effective still, is binocular dichoptic training. Today we will only illustrate briefly what this training is, as we are going to devote a whole blog on that soon.
If you are not totally new to our website, then I bet you already have quite a good hunch about what this training might be – and our Amblyoplay is one of them! In short, it is a vision training that encourages children to use both eyes equally, thus improving vision in the amblyopic eye. It is also a vision training that was scrutinized in numerous controlled studies – again, something we will discuss in further detail in the next blog. The critical feature of a successful binocular dichoptic training is that training exercises can only be carried out correctly if one is using both their eyes. This then encourages the child to use the amblyopic eye, which leads to the reduction of suppression of the amblyopic eye, which eventually leads to the improvement of vision in this very eye.
What’s the take-home message? There are many different ways of solving this issue and the studies indicate that the best is the combination of ophthalmologist’s instructions (refractive correction and patching) and complementing this whole training process with binocular dichoptic training (such as Amblyoplay). Stay tuned, as we prepare a blog targeting binocular dichoptic training in depth! Thanks for reading!