A Simplified Approach to Evaluate Retinal Blue Light Hazard Using the Correlated Color Temperature of LED Light Sources

Background: Visible light of short wavelength (blue light) can damage the retina cells, called blue light hazard. To protect the retina, permissible exposure limits have been determined by ICNIRP (the International Commission on Non-Ionizing Radiation Protection) and other health and safety agencies. These limits include complex physical concepts, and their evaluation requires light measuring instruments equipped with a blue light hazard function filter, which is not available at the moment in developing countries. This study aims to assess retinal blue light hazard using the correlated color temperature of Light-Emitting Diode (LED) light sources. Methods: In this study, a new method was proposed for evaluating the retinal blue light hazard using only the Correlated Color Temperature (CCL) of LED light sources for which concern on blue light hazard has currently been reinforced. In the proposed method, the radiometric quantity (blue light effective radiance) in W.m-2.sr-1 was converted to the corresponding photometric quantity (blue light effective luminance) in lm.m^-2.sr^-1. Then a computer code was developed for relevant calculations. Results: The estimated permissible exposure times applying the new photometry approach were highly reliable and supported by the literature. The proposed method is particularly useful because it eliminates the need to utilize any light measuring device. Conclusion: The new approach makes the concept of blue light hazard straightforward and understandable for all specialists dealing with optical radiation safety.