Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting

Evidence summary

There is a considerable scientific evidence for using a camera to measure changes in the skin's absorption of light, to indirectly measure vital signs (remote photoplethysmogram). However, there is currently no published evidence for Lifelight First. The preliminary results of 2 ongoing studies, including a mixed population of 8,712 inpatients, outpatients and healthy volunteers, have been summarised in this briefing.

The clinical evidence and its strengths and limitations is summarised in the overall assessment of the evidence.

Overall assessment of the evidence

The current evidence base lacks peer-reviewed published evidence. The data summarised in this briefing are made up of a single-arm observational study and a validation study including healthy volunteers. Because the evidence is unpublished there are significant uncertainties such as reproducibility of the data and reliability of the findings. The evidence base would benefit from a published, well-designed validation study comparing the clinical observation recorded by Lifelight First with best practice for people having routine monitoring for heart rate, blood pressure and respiratory rate.

Both studies reported in this briefing were done in the UK, comparing measurements by Lifelight First with current gold standard practice in the NHS.

Vision D study (unpublished)

Intervention and comparator(s)

Lifelight First compared with UK standard care measures using Welch Allyn Connex Monitor (heart rate and blood pressure) and manual counting (respiratory rate).

Key outcomes

The unpublished manuscript reports the accuracy of Lifelight First using root mean square (rms) differences in measurement readings. Lifelight First is comparable to other medical-grade benchmark technologies but has a slightly increased rms than the gold standard, a difference of about 1 to 2 beats per minute. The respiratory rate measures had similar accuracy to clinical-grade impedance tomography devices but was less accurate than pulse oximeters. Blood pressure measurements achieved mean error values that met national standards (BS EN ISO 81060-2:2014) and 95% Bland Altman limits were comparable to the limits published for widely used blood pressure monitors.

Strengths and limitations

This is an unpublished manuscript that has not been peer reviewed. This large study reports the findings from real-world data obtained in the NHS. The reference standard, comparators and the clinical setting are relevant to the NHS. The manuscript states that data are still being reviewed, so findings reported in this briefing may change. No accuracy outcomes such as sensitivity and specificity were reported. The data are being used to improve the algorithm, so the technology described in the manuscript is likely to be different than the commercially available product.

Validation study (unpublished)

Study size, design and location

Validation study evaluating the safety and performance of Lifelight First in 127 healthy volunteers during rest and exercise under laboratory conditions in the UK.

Intervention and comparator(s)

Lifelight First compared with UK standards of standard care measures using Welch Allyn Connex Monitor (heart rate and blood pressure) and manual counting (respiratory rate).

Key outcomes

Heart rate measurements reported by Lifelight First had an rms difference of 4.2 beats per minute. The rms difference for respiratory rate was 3.4 beats per minute. 89.5% of measurements had an error of 5 beats per minute or fewer. Lifelight First's mean error for blood pressure measurements meets national standards (BS EN ISO 81060-2:2014) and achieves grade D (systolic measures) and grade B (diastolic measures) when assessed against British Hypertension Society protocol requirements for cuff-type sphygmomanometers.

Strengths and limitations

The study is reported as an unpublished manuscript and has not been peer reviewed so may change before it is published. The study is primarily to report the safety and performance of the technology and is not intended to present clinical outcome data. The study includes post-hoc analysis which may bias findings. Additionally, the people included and the setting of the study are not generalisable to a clinical care population and setting.


The company claims there would be a reduction in consumables needed for monitoring vital signs in current care, as well as reduced need for personal protective equipment because the technology is contactless. There is no published evidence to support these claims.

Recent and ongoing studies