Workers ask whether the test light is safe for their eyes. What should we say?
Documented light-hazard tests evaluated the stimulus against specified safety limits.
The light stimulus was evaluated for light-hazard safety according to ISO 15004-2.2 and ANSI Z80.36, the international and US standards for light-hazard protection of ophthalmic instruments. Because a smartphone is not a standard ophthalmic instrument, it was assessed against the stricter Group 2 limits, which apply to instruments for which a potential light hazard exists.
The evaluation measured the smartphone flash at full intensity, 8 cm from the eye, for 4 seconds. The results for all flash types tested were well below the limits:
| Quantity | Measured range | Limit | |----------------------------------------------------------|--------------------|--------------------------------| | Weighted retinal visible and infrared thermal irradiance | 0.040–.096 W/cm² | 0.706 W/cm²(ISO) | | Weighted retinal radiant exposure (4 seconds) | 0.033–.084 J/cm² | 10 J/cm²(ISO); 2.2 J/cm²(ANSI) |
The flash emitted no significant ultraviolet or infrared radiation.
The evaluation was published in a peer-reviewed paper: D.M. Calandra, S. Di Martino, D. Riccio, and A. Visconti, "Smartphone Based Pupillometry: An Empirical Evaluation of Accuracy and Safety," ICIAP 2017, Lecture Notes in Computer Science 10485, pp. 433–43, Springer, 2017, https://doi.org/10.1007/978-3-319-68548-9_40. The study was conducted by researchers at the University of Naples Federico II, with SOBEREYE's founder as co-author.
The evaluation covered the iPhone models compatible with the SOBEREYE measurement set-up at the time of the study (5s, 6, 6s, SE, 7, and 7 Plus), used with an enclosure holding the smartphone 8 cm from the eye.
SOBEREYE applies the same evaluation approach to every smartphone model introduced in Devices after the study, and uses only models whose light exposure is within these safety limits.