A remote blood-pressure app built around a single job: take a reading and log it, guided gently, for someone using a health app for the first time. The brief was never “add bigger fonts”, it was to design so well for a 74-year-old that everyone else gets the better product too.
Margaret is 74. She was recently diagnosed with hypertension and told to take her blood pressure at home. She has never used a health app. Her vision is reduced, her hands are less steady than they were, and when an app does something she did not expect, she stops, because she assumes she broke it.
Most health apps treat her as an edge case to accommodate after launch. This one had to treat her as the primary user from the first screen.
The reading depends on a Bluetooth cuff, hardware that fails, disconnects and runs out of battery. Most apps hide that dependency until it breaks, then present a technical error.
The real problem was honesty under failure: how do you tell a nervous first-time user that a device is not connected, without her concluding that she has done something wrong? Every error state had to be blameless and recoverable.
Research Insights
Roughly half of patients prescribed home blood-pressure monitoring stop within months. Abandonment is rarely about the clinical value, it is about friction, uncertainty about correct technique, and the absence of feedback confirming the effort is worth anything. (Source: AHA Home BP Monitoring Scientific Statement)
WCAG AA sets 4.5:1 for body text; AAA sets 7:1. For users with age-related vision loss the difference is the gap between readable and legible. Setting 7:1 as the floor rather than the aspiration meant the palette had to be designed around contrast, not corrected for it afterwards. (Source: WCAG 2.2 Contrast Guidance)
Talking, crossed legs, a full bladder, or an unsupported arm can shift a reading by clinically meaningful margins. A monitoring app that only records numbers without coaching posture is collecting data that may actively mislead the clinician reading it. (Source: ESH Home BP Measurement Guidelines)
The brief supplied Margaret. Rather than broadening her into a segment, I kept her specific and added the two people who orbit her. The adult child who set the phone up, and the care coach on the other end of the readings. Designing for a named person made every trade-off concrete.
The governing rule throughout was that Margaret is not a constraint on the design, she is the design target. Every decision was tested against her first, and repeatedly the version that worked for her was simply the better version. Larger type forced tighter copy. Bigger targets forced fewer actions per screen. The accessibility work made the product better, not merely compliant.
The hardest requirement was not any single token, it was that every one of the eight accessibility controls could be combined with any other and nothing could break. Triple text size with bigger buttons and roomier spacing is a brutal layout test, and passing it is what forced the one-job-per-screen rule to hold everywhere.
Body text at 7:1 contrast minimum: AAA, not AA. Colour is never the only signal: every status is colour plus icon plus word. One clear job per screen, stated at the top.
Errors are blameless and always recoverable, and a named human. Dana, is reachable in one tap from anywhere in the app.
Every layout is verified at the largest text level with bigger buttons and roomier spacing enabled simultaneously. The worst-case combination, with no clipping, no overlap and no horizontal scroll.
High contrast drops translucency entirely rather than tinting it, so frosted-glass surfaces degrade to solid rather than to muddy.
Body text at 7:1 contrast minimum: AAA, not AA. Colour is never the only signal: every status is colour plus icon plus word. One clear job per screen, stated at the top.
Errors are blameless and always recoverable, and a named human. Dana, is reachable in one tap from anywhere in the app.
Every layout is verified at the largest text level with bigger buttons and roomier spacing enabled simultaneously. The worst-case combination, with no clipping, no overlap and no horizontal scroll.
High contrast drops translucency entirely rather than tinting it, so frosted-glass surfaces degrade to solid rather than to muddy.
The Eight Controls
| Setting | What it does |
|---|---|
| Larger text | Scales all type across three levels, shown as a three-dot level indicator rather than an abstract slider |
| High contrast | Switches to an AAA-leaning solid palette, dropping translucency entirely |
| Clear font | Swaps the entire interface to Atkinson Hyperlegible, designed for low vision |
| More spacing | Roomier line height and padding for users who track lines with difficulty |
| Bigger buttons | Raises every touch target to 72dp or above for less-steady hands |
| Reduce motion | Freezes all animation, including the gauge draw and count-up numbers |
| Vibrate on tap | Real haptic confirmation that a tap registered, critical for tremor |
| Read pages aloud | Text-to-speech narrates each screen automatically as the user navigates |
Structure studies for a device flow, where a wrong step costs a reading rather than a click.
Pairing and measuring are the two screens that decide whether this product gets used twice. Both were worked out in grey, because a hardware flow has to hold up for someone who is anxious, older, and holding the device in one hand. If the next action is not obvious without colour, it is not obvious.
The finished app reads as a warm, premium health companion rather than a medical device readout. Warm linen canvas, petrol-teal and coral, frosted glass cards and soft depth. Type is large by default and scalable by choice. Every status carries colour, an icon and a word, so nothing depends on seeing a hue correctly, and Dana is one tap away from every screen.
Design Highlights
Vantage Care, home gauge, the measure state, and a plain-language result
Designed and built end-to-end, from the assignment brief through an interactive HTML prototype to a running native Android application with real scheduled alarms.
Vantage Care was designed and built as a working native Android application with real scheduled alarms, persisted profile data and a full accessibility layer. The measures below describe what the product actually does, the honest metric set for a self-directed build.
"The brief said: design it so well for Margaret that it works for everyone. I assumed that meant accepting compromises for her sake. It did not. Larger type forced me to cut the copy to what actually mattered. Bigger targets forced fewer actions per screen. Blameless errors made the writing better everywhere. Almost nothing I did for Margaret made the product worse for anyone else. The constraint kept producing the better design rather than the accommodating one."
"The moment the project turned was when I stopped styling for seniors and started handing over the controls. Applied globally, senior-first design is a judgement about someone. Offered as eight switches, it is a question. That change cost very little to build and it is the difference between an app that accommodates Margaret and one that respects her."
Every screen below is captured from the running build on device. Step through the full set with the arrow keys, or click any screen to open it full size.