The OECD estimates that about 10% of the total world population, so about 650 million people are disabled. Therefore, attention to interface design for these people in app development should not be a niche topic but a priority for those who intend to develop apps for a wide audience.
How to design apps for people with disabilities.
There are four domains of accessibility to be considered when designing applications to meet the needs of users with disabilities:
– Vision: a person may be blind, color-blind, or have a visual challenge that makes focusing difficult.
– Hearing: a person may be deaf, have partial hearing loss, or have difficulty hearing sounds within a certain range.
– Physical and motor skills: a person with limited mobility may have difficulty holding a device or touching the interface.
– Learning and literacy: a person may have difficulty remembering a sequence of steps or find an overly complex user interface too difficult to process and manage.
Most modern mobile apps are poorly adapted for use by people with disabilities. iOS has special accessibility features built in, however to make them work properly the app interface should meet certain requirements:
- Easy-to-Read Text
- Simple structure
- Animations kept to a minimum
- Easy-to-touch buttons
- Presence of icons, illustrations and audio files
When choosing a character, it is necessary to consider the perception specifications of elements with complex structure (a, e, o, u). Their glyph should be easy and unambiguous to perceive.
The importance of font choice should never be underestimated as it really affects the entire app experience and, therefore, accessibility. However, we recommend using San Francisco, which is an iOS system font primarily because it is dynamic and easy to read.
It is well known that people suffering from color blindness have a limited perception of the color spectrum, which means that colors do not carry enough information and to facilitate its perception one should rely on the intensity of colors and not the colors themselves.
To facilitate the perception of the app, we recommend improving the contrast of the interface. In accordance with Web Content Accessibility Guidelines (WCAG) 2.0, the background and foreground color should be contrasty enough to be seen both on a monochrome screen and by people with limited color perception.
The contrast ratio must not be less than 4.5: 1 i.e. a black and white image has a maximum contrast ratio of 21: 1.
The complex multilevel interface can be a real problem for people with disabilities, especially those with visual and motor impairments. That is why it is so important to keep it simple and consistent.
Animations kept to a minimum
Fast screen flashing is not safe for people with photosensitive epilepsy; flashes with a frequency range of 4 to 59 Hz are strongly prohibited.
Buttons should be large enough to be clearly visible and easy to touch, which is useful for users with motor impairments. According to the rules that buttons should be at least 9 mm high and wide, and there should be enough free space around them.
Presence of icons, illustrations and audio files
Add icons, illustrations or audio files to the text to improve its perception by people with disabilities.
Apple's directions for accessible design.
On iOs there are features already built in by Apple that promote accessibility. VoiceOver: VoiceOver is one of the most important because it helps a wide range of users.Enabling VoiceOver in the Settings app, under General> Accessibility.
Apple has also provided a guidance document, here are some of the suggestions:
- Ensure that all items have accessibility labels. Labels should be as short as possible, ideally one word.
- You can also add accessibility tips that are read after the label. These are designed for novice users who need more information, but some people recommend using them only when necessary.
- Your suggestions should begin with a third-person singular verb that completes the phrase "this button ..." or "this control ...". For example, "Adds a song to the playlist." Ending with a period or period allows VoiceOver to read the suggestion more naturally.
- If the app is localized you have to do this for labels and accessibility tips as well.
- VoiceOver reads to the user what it sees on the screen by default but it is advisable to do a trial use to realize what it actually reads. For example, Tweetbot shows "8m" on the screen but reads "8 minutes ago" with VoiceOver.
To learn more, you can READ THE APPLE DOCUMENT ON ACCESSIBILITY. https://developer.apple.com/design/human-interface-guidelines/accessibility/overview/introduction/