The Technology
Contactless and accurate blood pressure readings ¹'²
When your heart beats, your skin “micro blushes”¹
Undetectable by the human eye, Lifelight captures these tiny changes in colour, analyses the signal and provides reliable pulse and blood pressure measurements.¹'²
Lifelight uses the same scientific principles as existing wearable devices - photoplethysmography (PPG)¹ – developed to be fully remote, negating the need for physical contact, extra equipment or calibration.²
Trained on thousands of pulse readings in trials, Lifelight’s AI model delivers measurements.²'³
BP, blood pressure; bpm, beats per minute; mmHg, millimetre of mercury; RGB, red, green, blue; VS, vital signs.
Adapted from Heiden, et al. 2022.³
Established science combined with advanced machine modelling
PPG uses light to detect the movement of blood around the body.⁴ Because blood absorbs more light than the surrounding tissues it is possible to measure changes in blood volume using either the light transmitted through, or reflected by, an area of the body.⁴
Lifelight detects tiny colour changes of the face with each heartbeat by measuring the reflected light using the integral camera on a smart device.¹'³ This is turned into a stream of numbers for each colour channel - red, green and blue (RGB). The anonymised colour signal is sent to the cloud to be processed by Lifelight’s algorithms.¹
Step 1: Pulse
By recording the changes in face colour over time, Lifelight can calculate how often the blood flows in – i.e. the pulse. Lifelight filters out signals from movement or external sources and checks for consistent data during the reading before calculating the mean pulse rate.¹
Step 2: Blood pressure
Once the pulse rate has been established, Lifelight cleans the signal again using different filters to remove unrelated data.¹ A unique transfer function transforms the signal into a carotid arterial pressure waveform. Further analysis including data from the most relevant colour channel creates further waveforms which are, together, used to report features that correlate with arterial stiffening and are indicative of blood pressure.¹
The prediction of systolic and diastolic blood pressure is performed separately using the most appropriate machine learning model for each parameter.
Lifelight has been issued with Class IIa certification for its blood pressure and heart rate readings and can be considered as equal to traditional measurement methods such as the cuff.²'⁵
Lifelight has one of the largest clinical databases of rPPG with pulse and BP readings from thousands of individuals.
Lifelight has been tested in extremes of both hyper and hypo tension.³ Lifelight is currently approved for use in adults aged 18 years and older.⁷ Trials in the paediatric population are ongoing.⁶
Lifelight has been shown to be unaffected by skin tone as assessed by the Fitzpatrick Scale.³
“The ability for our patients to have their blood pressure and other vitals checked at the same time as receiving their Covid or flu vaccine just makes sense for both patient and the NHS. We’re finding patients who had no idea they had hypertension getting picked up by Lifelight.”
Tim Cooper, Deputy Chief Medical Officer
Hampshire and Isle of Wight Integrated Care Board
Patient confidentiality is a key priority. All data is anonymised and not processed or stored on the device used to take the reading. Although Lifelight does require some basic biometrics, no other personal identifiable data is captured.
Product images shown on our website are for illustrative purposes only and not an exact representation of the product.
Lifelight is compatible with a range of validated mobile devices. Please contact us for a complete list.
