The battery is about the size of a grain of rice. It contains no liquid electrolyte. And on 22 April 2026, it was placed inside a contact lens that still fits on a human eye.
That is the core claim behind a proof-of-concept device announced jointly by XPANCEO and ITEN, a Dubai-based smart lens developer and a French solid-state battery manufacturer, respectively. Their prototype integrates a solid-state microbattery into the curved profile of a contact lens without obstructing the wearer’s vision. If the technology matures, it could crack open a problem that has defeated some of the best-funded labs in the world: how to reliably power electronics that sit directly on the eye.
But a working lab sample and a product you can buy are separated by years of testing, regulatory review, and manufacturing scale-up. Here is what the announcement actually shows, what it leaves unanswered, and why the history of smart contact lenses should make anyone cautious.
Why solid-state chemistry changes the safety math
Conventional lithium-ion batteries rely on liquid electrolytes to shuttle ions between electrodes. That liquid can leak, swell, or overheat. Inside a phone, rigid casings and thermal management systems keep those risks in check. On the surface of a cornea, none of those safeguards are available, and any failure could injure one of the most sensitive tissues in the body.
Solid-state batteries swap the liquid for a solid ion conductor. The result is a cell that eliminates the leakage risk entirely and significantly reduces the chance of thermal runaway. Those two properties matter enormously when the device sits millimeters from living tissue. However, solid electrolytes are not immune to mechanical failure. Under repeated flexing, some solid electrolyte materials can crack or delaminate, a concern that is especially relevant for a device bonded to a flexible lens substrate that bends with every blink. That fundamental safety advantage, tempered by real mechanical unknowns, is what makes the XPANCEO-ITEN approach different from earlier smart lens efforts that relied on conventional cell chemistry or external wireless power.
The engineering constraints are still punishing. The entire power source must occupy a sub-millimeter form factor, survive constant exposure to tear fluid, tolerate the mechanical stress of tens of thousands of blinks per day, and remain comfortable enough that a wearer barely notices it. Even demonstrating feasibility at that scale is a meaningful step forward in microbattery design.
ITEN’s track record in miniaturization
ITEN is not new to extreme-scale battery work. The company has collaborated with A*STAR’s Institute of Microelectronics in Singapore on embedding solid-state cells directly into semiconductor-style chip packages. A*STAR is a major government-funded research agency with deep expertise in fabrication, and its decision to partner with ITEN signals that the underlying technology has survived serious institutional vetting.
That said, the Singapore project targeted rigid chip packaging, not the flexible, bio-exposed substrate of a contact lens. It is best read as evidence that ITEN’s platform works at very small scales, not as direct validation of the smart lens application.
What the prototype does not yet show
A proof of concept demonstrates that something can work in principle. It does not demonstrate that it works reliably, affordably, or safely enough for consumers. Several critical gaps remain open.
Neither XPANCEO nor ITEN has disclosed energy density, cycle life, or recharge time for the microbattery. Without those numbers, there is no way to assess whether the cell can store enough energy to drive useful functions such as health monitoring sensors, low-power wireless data links, or a heads-up display element. A battery that fits inside a lens but lasts only minutes would be a novelty, not a breakthrough.
Biocompatibility is equally unconfirmed. Placing any electronic component on the eye demands rigorous safety validation: cytotoxicity assays, irritation studies, and extended-wear trials. No such results have been released. “Safer than a liquid-electrolyte lithium-ion cell” and “safe for prolonged contact with the human eye” are very different claims. Only the first has been made.
Regulatory clearance is likely years away. A smart contact lens with an embedded battery would almost certainly need approval from the U.S. Food and Drug Administration, European regulators, or both before it could be sold to consumers. No submission timeline has been announced. For novel combination devices that blend medical-device and electronic functions, the journey from lab prototype to market authorization is notoriously long. Neither company has offered a projected timeline.
Scaled manufacturing presents its own unknowns. Solid-state batteries have historically been more expensive to produce than conventional cells. Shrinking them to sub-millimeter dimensions on flexible substrates adds another layer of fabrication difficulty. Neither company has shared a production roadmap or target price.
Finally, the announcement does not specify how the microbattery would be recharged once depleted, or whether the lens is intended for single use. Competing approaches, such as radio-frequency energy harvesting, avoid onboard storage entirely by beaming power wirelessly to the lens. Each method carries trade-offs in complexity, cost, and energy availability. XPANCEO has not yet explained why an embedded cell is preferable for its use case.
A field littered with failed attempts
Smart contact lenses have a sobering history. Google and Verily Life Sciences spent roughly four years developing a glucose-monitoring lens before shelving the project in 2018, citing an inability to get reliable sensor readings through tear fluid.
Mojo Vision, a California startup that raised more than $200 million to build an augmented-reality contact lens with a built-in microLED display, shut down in early 2023 after failing to advance beyond limited prototypes. Google subsequently acquired key Mojo Vision assets, folding the team’s display expertise into its own hardware efforts. In both cases, delivering adequate power to the lens was among the core unsolved problems.
That track record matters. The XPANCEO-ITEN prototype addresses one piece of the puzzle, the power source, but a commercially viable smart lens also requires reliable sensors, low-power wireless communication, a usable interface, and a manufacturing process capable of producing millions of biocompatible units at an accessible price. Solving the battery problem is necessary but nowhere near sufficient.
Where solid-state microbatteries could reshape wearable and implantable devices
If ITEN’s solid-state microbattery technology proves manufacturable, contact lenses may turn out to be the most dramatic application rather than the most practical one. Hearing aids, continuous biosensor patches, neural interface implants, and even ingestible diagnostic capsules all face the same fundamental constraint: they need power sources that are tiny, safe for prolonged body contact, and resilient in harsh biological environments.
For now, the XPANCEO-ITEN announcement is best understood as an early but genuine milestone. The physics of powering electronics on the human eye are becoming feasible. The safety record, the business case, and the regulatory pathway have yet to be built. Readers tracking this space should watch for three signals in the months ahead: published performance benchmarks, biocompatibility study results, and any regulatory pre-submission filings. Until those surface, the rice-sized battery remains a promising laboratory achievement, not a device headed for store shelves.
