4. Discussion
The aim of the present study was to investigate the conjoint
impact of luminance and illuminance on visual fatigue and arousal
during prolonged digital reading (one hour) using a multidimensional
approach based on eye, performance and subjective measures.
Results showed that some of these measures were
sensitive to luminance, others to illuminance, and others again to
specific combinations of luminance and illuminance levels. Two
groups of variables were selected according to their sensitivity
and reliability in detecting changes in visual fatigue and
arousal, and one variable aimed at verifying the nature and quality
of recall.
Concerning visual fatigue, results on BR indicated that reading
under high screen luminance leads to a decrease in the frequency
of blinks with respect to low screen luminance. This result is in line
with a large number of studies (for a review see Rosenfield, 2011)
wherein higher levels of light intensity are usually associated with
a decreased frequency of blinking and an increased rate of tear
evaporation, each of which contributes to dry eyes, one of the main
factors for visual fatigue (Benedetto et al., 2013). Results on VFS
revealed that subjective visual fatigue significantly increased after
reading. However, no effects of either luminance or illuminance
were found. This absence of effects is in line with previous studies
that employed this measure for quite similar purposes (e.g.
Buchner & Baumgartner, 2007; Lee et al., 2011). Furthermore, it