The difference between managing a condition and living with one
For years, the promise of knowing your blood sugar without a needle has lived just beyond the reach of consumer technology — but a quiet SEC filing from a British sensor company may signal that the wait is nearly over. Apple, long rumored to be pursuing non-invasive glucose monitoring, appears to be the dominant force behind Rockley Photonics, a firm whose optical sensors can read biological signals with extraordinary precision. If the technology matures as expected, the Apple Watch 8 could arrive in 2022 carrying a capability that would spare millions of diabetics from costly, cumbersome external devices. It is a reminder that the most consequential health revolutions sometimes announce themselves not in press conferences, but in regulatory paperwork.
- Diabetics currently pay over $1,280 a year for continuous glucose monitoring — a burden that a wrist-worn sensor could erase entirely.
- Rockley Photonics' SEC filings expose Apple as its overwhelmingly dominant customer, making the partnership nearly impossible to dismiss as coincidence.
- The company's laser-based sensors claim resolution up to a million times sharper than existing LED wearable technology, raising the stakes for what non-invasive monitoring could actually deliver.
- Apple is deliberately skipping the Watch 7 for this feature, signaling that reliability — not speed to market — is driving the timeline toward a 2022 launch.
- Beyond diabetes, the technology could reframe the Apple Watch as a metabolic health tool for a far wider audience, expanding its medical and commercial reach simultaneously.
Apple has been chasing blood glucose monitoring on the wrist since at least 2017, when Tim Cook was spotted wearing a prototype on campus. Years later, the Apple Watch still cannot do it without expensive external hardware — but a filing with the SEC suggests that may be changing, and the signal comes from an unexpected source.
Rockley Photonics, a UK-based sensor manufacturer preparing to go public, disclosed that Apple was its largest customer by an overwhelming margin — accounting for virtually all of the company's revenue in both 2019 and 2020. Rockley's technology uses optical lasers to read biological signals non-invasively, including lactate, blood pressure, body temperature, and glucose. The company claims its sensors offer up to a million times higher resolution than the LED-based solutions currently found in wearables — a level of precision that matters enormously when tracking something as medically sensitive as blood sugar.
The human stakes are real. Continuous glucose monitoring devices like Dexcom currently cost diabetics upward of $1,280 annually. A sensor embedded in a watch already on your wrist would eliminate that expense entirely — and could appeal well beyond the diabetic community to anyone curious about how food affects their metabolism.
Still, obstacles remain. New sensors introduce tradeoffs in battery life, device thickness, and price. Apple appears to be taking its time, with blood glucose monitoring now targeted for the Watch 8 in 2022 rather than the Watch 7 expected this fall. Rockley's CEO declined to confirm Apple's involvement publicly, and Apple itself has said nothing. But the SEC filing is unambiguous: Apple is deeply invested in this technology, and the quiet patience of its approach suggests it intends to get it right.
Apple has been chasing the dream of blood glucose monitoring on its wrist for years. Tim Cook was spotted on campus wearing a prototype as far back as 2017. But the Apple Watch still can't do it—not without strapping on expensive external hardware that costs diabetics over a thousand dollars a year. That may be about to change, and the clue comes not from Apple's own announcements, but from a company about to go public.
Rockley Photonics, a UK sensor manufacturer, filed documents with the SEC that reveal Apple as its largest customer by a significant margin. In 2020 and 2019, Apple and one other customer accounted for essentially all of Rockley's revenue—100 percent and 99.6 percent respectively. The company makes optical sensors that can read multiple biological signals without invasive equipment: lactate, alcohol, carbon monoxide, blood pressure, blood oxygen, core body temperature, and glucose. For someone tracking the Apple Watch rumors, that last one stands out.
What makes Rockley's technology noteworthy is its precision. The company claims its lasers offer up to a million times higher resolution than existing LED solutions in wearables, a thousand times greater accuracy, and a hundred times broader wavelength range. That kind of specificity matters when you're trying to measure something as variable and medically important as blood sugar levels. The Telegraph uncovered these filings, and while Rockley's CEO Andrew Rickman told the publication he expects the technology in consumer products next year, he declined to confirm whether Apple would be the first to use it.
The potential impact is substantial. Right now, diabetics who want continuous glucose monitoring rely on devices like Dexcom, which costs $245 for transmitters and over $1,000 for three months of sensors. That's roughly $1,280 a year for the privilege of knowing your blood sugar in real time. A non-invasive sensor built into a watch you're already wearing would eliminate that burden entirely. Beyond diabetes management, such a feature could appeal to anyone interested in understanding how their diet affects their metabolism—a broader market that Apple might find more marketable than positioning it purely as a medical device.
But there are obstacles. Adding new sensors to a watch raises questions about battery life, device thickness, and cost. The Apple Watch 7 is expected this fall, but blood glucose monitoring is being pegged for the Watch 8 in 2022. That timeline suggests Apple is being cautious, taking time to ensure the technology is reliable before putting it in millions of wrists. The company's legendary secrecy around supplier relationships means Rockley won't confirm anything publicly. Still, the SEC filing speaks clearly: Apple is betting on this technology, and betting big.
Citas Notables
Rockley's two largest customers collectively accounted for 100% and 99.6% of Rockley's revenue in 2020 and 2019, respectively.— SEC filing from Rockley Photonics
Rockley CEO Andrew Rickman expects the technology in consumer products next year, though he would not confirm whether it would be in an Apple product.— Andrew Rickman, Rockley Photonics CEO, to The Telegraph
La Conversación del Hearth Otra perspectiva de la historia
Why would Apple care so much about blood glucose monitoring that it becomes the largest customer for an entire sensor company?
Because it's the one health metric the Watch still can't measure without external hardware. Everything else—heart rate, blood oxygen, temperature—is already there. Glucose is the gap, and it's an expensive gap for millions of people.
But couldn't they just partner with Dexcom or another existing player?
They could, but that's not Apple's way. They want to own the technology, control it, integrate it seamlessly. Rockley's sensors are built on optical technology that's fundamentally different from what's out there. That's worth paying for.
The filing says Apple is their largest customer but doesn't name Apple directly. How confident are we this is real?
The Telegraph connected the dots through the SEC documents. Apple's size and Rockley's sudden revenue spike in 2019 and 2020 align perfectly with when these rumors started intensifying. It's not a quote from Tim Cook, but it's a financial paper trail.
If this works, what changes for someone with diabetes?
Everything. Instead of buying sensors every three months and wearing a separate device, you glance at your wrist. No additional cost, no additional hardware. It's the difference between managing a condition and living with one.
Why wait until 2022? Why not put it in the Watch 7 this fall?
Battery life, probably. Adding optical sensors that need to work all day without draining the battery is hard. They're taking the extra year to get it right.