Ten Design Principles for Improving User Interfaces

A successful medical device design is closely related to the quality of the user interface. In particular, as related R&D capabilities and application technologies mature and more and more competitors enter the market, the quality of the user interface becomes an important indicator for differentiating product levels.
As people place greater emphasis on healthcare, the market for medical devices has shifted from professional medical institutions to everyday home healthcare. Therefore, in order to gain a dominant market position and seize opportunities in this new market, in addition to extensive sales channels and excellent capabilities, superior user interface design is the best marketing tool.
In short, a good user interface design must meet the user's needs and take into account their physical and psychological state. A user-friendly and convenient interface not only increases ease of use but also reduces error rates, allowing medical devices to function at their maximum potential and ultimately benefiting the user. Of course, for manufacturers, their research and development efforts have even greater social and economic value. So, how can we design a truly excellent user interface, and how can we evaluate its rationality? Experts from the U.S. National Research Center have proposed ten design principles to address this issue, detailed below.

1. Reduce the visual density of the display.

Medical devices often require a lot of information to convey, easily resulting in a cluttered display/operation interface. With all the information crammed together, even long-term healthcare professionals may not be able to quickly grasp the necessary information or know how to use the device correctly, let alone casual users. Therefore, when designing a user interface, it is crucial to consider content arrangement and space reservation. Appropriate white space will make the entire interface look clear and aesthetically pleasing. Here are some methods for reserving space: Place secondary information in options or links, selecting only when needed; reduce the size of brand identification images, such as logos and names, avoiding excessive enlargement to emphasize brand image; use simple graphics, prioritizing 2D flatness and avoiding overly complex images; use white space, rather than lines, to distinguish text content, keeping the interface as simple as possible; use concise language to express messages, avoiding excessive content.

2. Provide users with search tools and guidance

Some users, after using mobile medical devices, become confused about where the information they painstakingly searched for has gone. This is because users don't understand the structure of the user interface. The National Center for Research in the United States recommends placing prominent and meaningful titles on the main and secondary headings, such as "Query," "Settings," or "Return to Home Screen," etc., which are simple and easy to understand. The query content can also be paginated, such as 15 of 1, 15 of 2, etc., so that users can roughly know how much information is available. Search options or controls should be placed in obvious and fixed locations so that operators can quickly find the required function whenever needed, reducing testing time and the error rate.

3. Design a reasonable text area plan

Some medical device displays look like a chessboard, with no sense of order whatsoever. Of course, sometimes an ingenious interface design may give users a refreshing and pleasing visual experience, but in any case, a well-organized text area layout is more likely to achieve the most effective and comfortable results.
Try to make the text flow smoothly and coherently. For example, consider a center-aligned block of text versus a left-aligned block. The left-aligned block is clearly much smoother to read because after reading a line, the user naturally continues reading to the lower left without needing to find the beginning again. In contrast, a center-aligned block looks much more cluttered. Therefore, well-organized text layout can significantly improve the quality of the user interface.

4. Increase visual balance

The balance of the display interface is quite important, especially on both sides of the vertical axis. The consistency of the sense of weight has a greater impact on the user's psychological experience. An asymmetrical visual plane makes the whole screen look tilted or as if something is missing; while a symmetrical visual plane looks neat and cohesive, has high recognizability, and conforms to user psychology.
As for how to increase visual balance, here are some methods: pay attention to the ratio of white space to text blocks; reduce overly fancy emphasis methods, such as excessive underlining, bolding, or 3D graphics; place all content blocks (including white space) in a complete square to create a sense of unity.

5. Avoid using too many colors.

In a user interface (including background and operation components), it is best not to use more than 3 to 5 colors. It is best to use light gray tones, such as light gray and white, for large areas. Important operation components should be represented by colors with higher saturation, such as red, blue, and green. However, there should not be too many colors, and the area should not be too large. Otherwise, it will look too cluttered and lose the original intention of emphasizing the key points.

6. Choose clear and elegant fonts.

In an interface, it is best not to have too many fonts, and it is even more undesirable to choose fonts that are too complex or weak, such as italics. The simpler and clearer the font, the better the legibility.

7. Using organizational classification instructions

Experiments have shown that a table-style interface structure offers the best recognizability. Information with the same attribute should be grouped under the same level to achieve comprehensive classification and easy configuration.

8. Use concise and to-the-point language.

Concisely highlight the key points; descriptive text will only make users lose patience and make the overall interface look complicated and difficult to understand.

9. Simplified Images (Icon)

Avoid using complex images; pictographic representations are best. The simpler the better, as long as it resonates with users.

10. Avoid inconsistencies in interface design

Whether using color or font to represent a certain meaning, consistency is essential. Red represents danger, and bold represents emphasis. These should never be used arbitrarily, otherwise it will cause confusion for users.
The quality of the user interface is closely related to the design of a successful medical device. Especially as related R&D capabilities and application technologies mature and more competitors enter the market, the quality of the user interface becomes an important indicator for product differentiation. In addition, the safety of medical devices is also related to the quality of the interface design, because design flaws can directly or indirectly cause errors during use, and in severe cases, may even cause injury or death to the user. Therefore, it is clear that the design of a product, especially medical products that are closely related to the human body, must be carried out with utmost care.
Of course, imperfections may sometimes occur in designs due to immature technology or a lack of complete understanding of user needs. However, regardless of the circumstances, a well-designed and user-friendly interface should be considered a fundamental responsibility and a source of pride for both manufacturers and designers. It is hoped that these design principles will provide manufacturers with clearer and more comprehensive design guidance and concepts when designing medical products, thereby enabling the development of more user-friendly and convenient medical products that ultimately benefit humanity.