Diversity, Equity & Inclusion

Designing more inclusive user interfaces

See how Ross Hannibal’s different view of the world is improving the user experience of linear accelerators for everyone.

4 min
Rebecca Murr and Sarah Hermanns
Published on February 9, 2023

Ross Hannibal has been designing linear accelerators at Varian, a Siemens Healthineers company, almost half his professional life. In his current role, he manages the innovation portfolio which also includes User Experience (UX) innovations. Ross seeks not only to meet the customer needs, but also to create inclusive and accessible user interfaces (UIs).

A careful design of user interfaces means that information and instructions are correctly communicated. One important aspect is color. However, if a user has a color deficiency or blindness, color can be challenging.

Colorblindness is a lot more common than people think. Worldwide, there are approximately 300 million people with colorblindness, almost the same number of people as the entire population of the USA. The most common types of colorblindness are due to the loss or limited function of red or green cone photopigments. This type of colorblindness is commonly referred to as red-green colorblindness but also includes all colors that contain red or green components. Ross Hannibal is affected, too.

It first showed up during his childhood when he lost a bright red sweater on a green lawn. “My mom noticed I couldn't find the sweater. That was the first hint,” Ross remembers. Today, he understands his limitations: “I can't tell the difference between something that's blue and something that's purple, because purple has red in it, so I can't see the difference.”

Ross Hannibal outside his workplace – the Varian headquarters in Palo Alto, United States.

Ross Hannibal steht vor der Varian-Zentrale in Palo Alto, USA

And this had a decisive impact on Ross’ career: “I went to school initially as an industrial designer, and for whatever reason, I didn't really think it would have an effect.” You need to have an eye for colors for this career, so he switched to engineering, which he really enjoys. Ross even sees his colorblindness as an advantage: “I can test interfaces to see how they would do with someone who has a color deficiency.”

For the last 20 years, Ross led the User Experience (UX) design of Varian’s linear accelerators (LINACs), which are used to treat cancer patients with radiation therapy. This role comprised of a variety of tasks, such as sketching to create the new UI layout, observing users performing their functions or doing a user task analysis to see where the workflow could be improved. Having a passion for sketching and design made Ross a natural fit for this task. But also his colorblindness makes him particularly well suited to this role. 

Today, he helps manage the innovation portfolio at Varian which also includes UX innovations. “I’m focusing on the bigger picture rather than specific interactions. For example, I’m working on making the LINAC design more accessible for pediatric patients”, Ross explains. “I want to create innovations that inspire not just the users, but everyone involved in providing quality cancer care.

A medical linear accelerator (LINAC) customizes high energy x-rays or electrons to conform to a tumor's shape and destroy cancer cells while sparing surrounding normal tissue.
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For Ross, good user interfaces are designed to be inclusive and accessible. “With my variation, I bring in the perspective of any partially or completely colorblind user. And by doing so, I make sure we are using multiple codes to increase the amount of people who are able to use the interface appropriately.” One way to achieve this goal is to add a second way to understand the message, for example by adding a shape or icon to clarify the communication.

The human variation model of disability defines disability as the systematic mismatch between physical and mental attributes of individuals and the present (but not the potential) ability of social institutions to accommodate those attributes.

Portrait of Ross Hannibal

For Ross, an inclusive design goes beyond creating specific products for certain users. It implies creating something that everyone can experience — no matter how different they are from each other: “When your design is inclusive, the user interface becomes better for everybody. And that's true for almost all types of disabilities or variations.” Ross himself knows the challenges of non-inclusive machine design all too well. An ordinary water dispenser for example often has a red and a green button – signs that Ross can’t encode, especially when the light is faint, and the buttons are small.

He is convinced: Everyone will have a variation at one point, either due to sickness, age, an accident, or some other circumstance. Not all of them might be apparent, but all deserve to be considered in the design process, no matter whether it’s an office space, a medical device, or a simple water dispenser. 

“I want to make sure that our designs are more sustainable, so that they help current generations without harming future generations,” he explains. For that, Ross teams up with colortypical colleagues. “Together, we can do better design, and this is what it’s all about: Anyone could have a variation, we are all different.” For him, bringing differences together is where true innovative strength and sustainability come from.

Portrait of Ross Hannibal

Ross believes that we all have blind spots, not just for colors and our visual field, but also in our beliefs, our ideas. “If we can change how we think about things, what our underlying beliefs are, it changes how we see the world."

By Rebecca Murr and Sarah Hermanns
Rebecca Murr and Sarah Hermanns are both editors at Siemens Healthineers.