Speaker
Description
Melanin pigment determines skin tone, where darker skin tones contain higher levels of melanin content. To examine the sensitivity of infrared optical technologies as a function of skin tone, 5 commercial pulse and cerebral oximeters were investigated on participants with varying skin tone (Brands: Masimo MightySat™, Blue Echo Care™, ToronTek-G64™, Apple Watch Series 10™, and NIRSport2™). The participants’ skin tones were determined by objectively measuring melanin content using a reflectance spectrophotometer, with skin tones ranging from Type I (Very Light) to Type VI (Dark) based on the Individual Typology Angle. Blood oxygen saturation (SpO2, %) and heart rate (HR, bpm) were measured before and after walking on a treadmill, to induce hypoxemia (SpO2 < 95 %). The gold standard pulse oximeter that is commonly used in clinical settings (Masimo MightySat™, wavelengths 660 nm and 940 nm, variable power), recorded a 5 % reduction in SpO2 and an increase in HR of 70 bpm across participants of all skin tones. Sensitivity measurements of the Apple Watch Series 10™ showed no change in SpO2 compared to the gold standard, across all participants. Compared to the gold standard, this device uses one of its wavelengths at 523 nm which is absorbed more by melanin and water compared to 660 nm wavelength, leading to poor device sensitivity. For participants with darker (Type 6) skin tone, the Blue Echo Care™ and ToronTek-G64™ pulse oximeters were not sensitive, showing no change in SpO2. Despite both pulse oximeters using similar wavelengths as the Masimo MightySat™, the low static power of the devices’ LEDs could explain their poor sensitivity for the darkest skin type. The cerebral oximeter generally measured a 1–2 % reduction in brain oxygen saturation across participants with skin tone types 1–5, and 0.5 % reduction for participants with the darkest Type 6 skin tone. These findings provide evidence for the potential for skin tone bias in the sensitivity of many infrared devices, which industry manufacturers need to be aware of. Future research will attempt to optimize near infrared device engineering in order to calibrate and correct for variations in individuals’ skin tone, toward personalized medicine and consumer products.
| Keyword-1 | Biophotonics |
|---|---|
| Keyword-2 | Pulse oximeters |
| Keyword-3 | Infrared Light |