Virtual Reality As A Binocular Treatment For Amblyopia

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In this article, we would like to discuss virtual reality as a binocular treatment for Amblyopia or lazy eye. And we would like to do it through the scientific paper ‘Binocular treatment of amblyopia based on virtual reality.’

This article was published in the ‘Revista Cubana de Oftalmología in 2016′ and elaborated by Yanet Cristina Díaz Núñez and Yenner Joaquín Díaz Núñez.

If you have ever wondered if eye patch vision therapy is your only option if you suffer from Amblyopia. These studies give us hope that better outcomes are possible.
Our goal is to better understand the difference between traditional treatments (monocular) with more current treatments that treat binocularity.

Diaz and Diaz’s article discusses two types of virtual reality-based systems: the I-BiT™ and anti-suppression.

The former works mainly on visual acuity, and the latter, in addition to visual acuity, on binocular vision.

The aim of other, more conventional treatments, such as occlusion of the ‘dominant eye,’ is to give strength through preference to the Lazy Eye so that it can improve its visual acuity.

However, this objective may have some disadvantages as it does not improve the coordination between both eyes, and coordination is required to achieve correct binocular vision.

Alternative treatments, such as the interactive binocular treatment I-BiT™ promote binocular work by treating both eyes utilizing virtual reality.

Visual acuity is worked with the help of both eyes and not only the amblyopic eye, as would be the case with occlusion of the dominant eye, which improves monocular vision.

When using virtual reality vision therapy, the amblyopic eye is preferentially stimulated, offering it the most active, dynamic, and exciting elements. And leaving the eye with better vision, the less interesting elements.

It includes anti-suppression treatments to treat the reduction of the suppression produced by the brain to discard one of the two images provided by the eyes.

Treatments are performed using video clips and video games for patients of different ages, both children and adults.

What is Binocular Vision?

In binocular vision, the information comes from both eyes, adequately complementing each other to achieve a vision with three dimensions, distance and movement of objects.

You can find more information here if you want to know more about binocular vision and stereopsis.

Interactive Binocular Treatment (I-BiT™)

The I-BiT™ system was developed by a group of researchers at the University of Nottingham (UK) virtual reality (VIRART). It represented the first virtual reality-based computer prototype for binocularly treating Amblyopia.

The aim of the I-BiT™ is the stimulation of both eyes simultaneously from software with interactive 2-D and 3-D videos and games via a binocular display (i.e., with two screens, one for the subject and one for the practitioner).

The amblyopic eye receives a central stimulus, and peripheral stimuli are presented to both eyes.

Treating Amblyopia using Video Clips?

In exercises using video clips, the image is divided into two parts:

The central area can only be viewed by the amblyopic eye, and the outer area by both eyes. Only the amblyopic eye can see the video clip since it is represented only on its screen.

Vision Therapy: Video Games and Virtual Reality

Download Our Guide About Amblyopia!

Video Games To Treat Amblyopia?

Video games are intended to provide the amblyopic eye with dynamic elements and the dominant eye with fixed elements. Giving each eye something different to visualize so that both eyes can work together to successfully complete the game.

Studies and research on these treatments continue. Games are being evaluated where the visual information is divided into three parts.

That is, one set of elements is provided to one eye, another group of elements to the other eye, and a third set of elements to both eyes. There can be static or dynamic elements in both the first and the second segments. And in the third group, only static details and the background scenery are present.

An example of this is used in an adapted version of the block game Tetris:

Each eye is given a part of the information, and then, a group of visual elements is shared with both eyes. From the falling block, a part of the piece is visualized in each eye, and the entire piece is only seen when the two eyes are merged in the third section.

Anti-suppression Binocular Treatment utilizing contrast

As optometrist Gloria Hermida comments in her blog and research shows: working on suppression is the key to treating Amblyopia.

Suppression refers to the brain’s eliminating one of the two images it receives from both eyes so as not to see double.

Every amblyopic person suffers from some degree of suppression. Where the brain inhibits the lazy eye, misaligning or defocusing, to avoid a double or blurred confusion.

This suppression, over time, triggers vision loss or more permanent Amblyopia.

Until now, clinical tests were designed to determine whether suppression was present.

However, by utilizing binocular contrast focusing, it is possible to measure suppression by artificially decreasing the contrast of the information perceived by the dominant eye, thus allowing a normal binocular combination.

For this purpose, two groups of moving dots are presented in a test. One of them is the signal, and the other is called noise. They all move at the same speed, and their appearance is the same.

But the dots belonging to the signal move in the same direction and in the same direction.

On the other hand, the noise dots move in a random direction.

Generally, the signal will be presented to the amblyopic eye, while the dominant eye will receive the noise. However, signal and noise can be shown differently to calculate contrast.

One way is to show both signal and noise to both eyes. And then, each group of moving dots to one eye in order to check the existing imbalance.

And finally, maximum contrast is applied to the amblyopic eye and none to the dominant eye. In this way, it will only be possible to perceive the signal, gradually adding more contrast to the dominant eye until the subject can identify the coherent direction.

The anti-suppression treatment, in the same way as in the I-Bit treatments indicated above, uses video clips and video games.

Anti-suppression treatment for Amblyopia with video clips?

For the vision of the video clip, the amblyopic eye is presented with the original version, and a modified version is given to the dominant eye, thus creating an imbalance by reducing suppression.

Anti-suppression treatment for Amblyopia with video games?

To play the game, suppression is reduced to create a dichoptic imbalance, allowing for a binocular combination.

In the same way, as indicated above, the Lazy Eye will receive stimuli with the highest contrast possible. At the same time, the other eye will have reduced contrast.

The amblyopic eye will always have the same contrast, while the contrast for the dominant eye will be modified.

Scientific Evidence for the Application of Virtual Reality as a Binocular Treatment for Amblyopia

Few trials can show the effectiveness of virtual reality as a binocular treatment for treating Amblyopia since both the treatment period and the number of study subjects were small.

In the studies with I-BiT™ treatments, only children were participating, while in the anti-suppression studies, both adults and children were studied. 

In the former, the aim is to improve visual acuity. In the latter, in addition to visual acuity, the aim is to achieve binocular vision and stereopsis. 

The studies highlight that this type of treatment achieves:

  • improvement in a shorter time than in other conventional treatments, 
  • Reduces acceptance problems: Occlusion therapy is highly invasive and other Vision Therapy exercises can be boring, especially for children.

These studies suggest that traditional treatments can be combined with binocular treatments, making them complementary for children and adults who have undergone previous treatments which have provided sufficient progress.

Remember to visit your eye care professional so diagnosis and treatment can best adapt to our situation and we can achieve the best possible outcome.