Experimental evaluation of ‘blue light’ optical filters: performance and classifications

The issue of ‘blue light exposure’ is a topic of considerable debate in scientific literature. The wide variety of potential impacts (positive and negative) illustrates the need for consistent metrics to report spectral parameters. In response, a comprehensive set of empirical data (greater than 20 filtering media, 20 different lighting conditions) was produced and analysed under a single common methodology. Data analysis identified three different groupings of filters. The results of this paper highlight the diverse behaviour from a selection of filter media, most of which claim, or report to have, ‘blue light filtering’ properties. This diverse behaviour means that the user of the filtering media may not obtain the expected performance due to inconsistencies in data reporting. This paper also provides an example of a low-cost, ‘fitness for purpose’ methodology, as well as general recommendations regarding the reporting of filter media data.