Using eye gaze interaction when designing products for people with paraplegia 

Eye Image

In the world of UX, many professionals discuss and disagree on a lot of topics. It can be the titles, the processes, the best methodology, or the best tools. But there is one thing that all UX professionals agree on, and it is that great products stand out by focusing on the needs of the end users. Empathizing with the users is the keyway that allows us to zero in on the main problems and make sure we are solving the right ones.  

As technology evolves, we are also rewarded with more tools in our arsenal that help us improve the experience for those end users.  

There is one specific user group that needs specific equipment and specific products built just so they can perform simple daily tasks that most of us take for granted. We are referring to paraplegics or people who due to illness or accident have become paralyzed and have limited to no ability to move their limbs. This article is devoted to explaining how designing products with eye-gaze technology and eye-gaze interaction can benefit this specific user group.  

Users

Wheelchair Accessible Symbol Sign

To be even more specific we will focus on, quadriplegics or tetraplegics which refers to people who are unable to move all four of their extremities. Quadriplegia happens in injuries between the C1 and C8 vertebrae or the C-spine region that is in the neck. Depending on the position and severity of the injury there can be various levels of paralysis. The higher the injury the more dangerous the effects that it causes are and most likely all four limbs will be paralyzed. 

As you can only begin to imagine how drastically such injuries affect the lives of people and how daily mundane tasks are now completely different. Something as simple as calling a relative can be an exceedingly difficult or in some cases impossible task without any assistance. That is why almost half of people (49.3%) who have become paralyzed due to an injury experiences mental health issues such as anxiety and depression

Technology

Yarbus eye tracker from the 1960s

That is where eye-tracking technology comes into play. The first eye tracker was built in 1908 and a big contributor to that role was the field of ophthalmology. The 1970s and 1980s were the biggest decades for eye-tracking technology and especially the research done in the late 80s was starting to shift the focus towards human-computer interaction. It helped researchers discover how people use computer interfaces and how to improve the experience. Along with that, the research on using technology for people with disabilities was also ongoing.  

With all that research and a lot of progress, today the latest XR devices such as HoloLens, Magic Leap, Pico, Meta Quest, and even the new ones that are about to hit the market such as Apple’s Vision Pro all leverage this technology to create a seamless experience for their users. Eye Trackers are placed in a strategic position on each device and eye calibration is one of the first setup options when starting to use the device. That is why the XR market is the perfect candidate for this kind of products that support eye-gaze interaction.

magic_leap_used_by_paraplegic_person
Paraplegic Person uses Magic Leap

Design

So, we already have the technology at our disposal, but this raises an important question for future UX designers. As designers, we also agree on the fact that making products accessible to a wider user group has a positive effect not only on the accessibility but the usability of the product as well. But how can we make sure that we include this group of people with this kind of disability when we design? The topic of accessibility has been getting more traction among designers and companies that strive to make their products accessible to a wider user group. Countries have also made accessibility standards that are required to be implemented in any digital product on the market. Currently, only 3% of the web is fully accessible to people with disabilities. And that is such a tiny fracture that points out the dire need to design for accessibility.  

So how do we design products that are inclusive and usable? As with everything in design, it takes innovation to drive those products forward. And discovering new methods of interacting with those products immediately increases the user group that can benefit from that product. When it comes to the specific user group we mentioned above, quadriplegics, having these new interaction methods is the only option they have to access the web or use apps for communication, entertainment, or media. 

Currently, we have specialized products on the market that use eye-gaze interaction methods but also require specialized equipment to be able to do so. Some examples include the assistive technology apps and products from Tobii Dynavox, Microsoft’s eye control option, or Apple’s option to control an iPad with the help of an eye tracking device.  

TD Pilot eye tracker for iPads
Tobii Dynavox’s TD Pilot eye tracker for iPads, photo from Tobii Dynavox 

Biology

When using your hands is not an option, using your voice or your eyes can be the only alternative. Eye-gaze interaction is tightly connected to the research and improvement in eye-tracking technology and ophthalmology. The two main eye movements consist of saccades and fixations. Human vision consists of alternating sequences between these two movements. Saccades are the rapid eye movements that happen between fixations which are the periods when the eye is still and focused. Understanding biology helps to understand how to design better user interfaces that allow eye-gaze interaction.  

Challenges 

There are many challenges even at the very beginning of designing such an experience. One of the biggest is time. It is critical to determine the amount of time it takes to activate an action on the interface. Not all eyes behave the same and not all people have the same eyes. The time interval should be tested and adjusted to accommodate the needs of many users. The best way to achieve this is to test users with different capabilities and determine the exact interval needed to trigger an action. This can also become a setting that users can adjust based on their needs. For example, when typing on a keyboard some people might take just one second to make a letter selection while for others 1,5 seconds might be more appropriate. Accommodating this need and allowing customization might improve the experience for a wider user group. 

Another challenge is designing the user interface. The basic principles are still in play but now we are designing for eye interaction instead of hand interaction. This will drastically affect the look and feel of the product. The sizing, visualization, and additional elements such as animation and sound are extremely important to highlight the actions and allow for seamless navigation and usability. Since we have already discussed the main eye movements it is also valuable to note that even the fixations of the eye are not completely fixed in one spot. The eye still moves in a radius around the target. This affects the sizing and styling of the elements in the user interface. 

Positioning the elements on the screen is also a key challenge. The user interface should be focused to accommodate quick navigation and placing the elements outside of the field of view can cause mistakes or actions that the user will not be able to trigger. Also keeping in mind that some quadriplegics have limited head mobility this can cause an even bigger challenge. The focus of the user should always be in the field of view which can vary from one user to another. 

Technology is also not widely available yet to accommodate such interaction methods to be used in all products. But as technology progresses the road to having eye-gaze as an additional method is becoming clearer.  

Using this method of interaction as a sole method can lead to many mistakes and frustrations for the users. To cure those frustrations a lot of testing and adjusting should be done in the initial phases of the design process. Testing is the strongest tool we currently have in our tool set. 

Opportunities

Eye-gaze interaction might be if not the most natural then definitely the first form of interaction for a lot of people. This creates a unique opportunity to explore the field and discover how our products can benefit from using the eyes as tools for interaction with digital products. A simple example is using the eyes to navigate a page on the web. Scrolling is a big UX issue and with traditional methods of navigation users always need either a mouse, a trackpad, or their fingers to scroll. Something as simple as looking down and having the page already scroll along is as simple and as intuitive as it can be. 

Apart from intuitive another benefit of using eye interaction is the already mentioned inclusivity of a wider user group. We should always be mindful of various levels of accessibility and make sure that the products we design are appropriate for people with different or limited abilities. 

Innovation is also another crucial point that no designer should forget about. We are always focused on building usable and practical products that we very often forget to be innovative and creative. And being innovative is one of the strongest characteristics of a great designer. Having this kind of technology allows for more innovation since it is still not widely used, and is still finding its place on the digital spectrum. 

That said, using eye interaction allows for more opportunities and more innovative products with increased usability and performance. Eye-gaze interaction is not solely a method that people with disabilities can benefit from. There are a million ways that we can incorporate this method of interaction in product design. That does not mean that every product should use eye gaze interaction but, since there is a large group of people that benefit from such interaction in digital products there is no reason, we should not think of ways to incorporate it in the design process. 

As such you can already see the importance of including eye-gaze interaction in building more accessible products. Augment IT has been collaborating with the Swiss Paraplegic Centre to create a product that will improve the lives of people living with quadriplegia, especially in the first few months in the hospital. 

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