Measuring eye fatigue of radiologist at reading room and daylight illumination conditions

Abstract

With the revolutionary development in technology, diagnostics methods that are used in radiology have started to change with visual display terminals; however, traditionally the ambient light should be as low as feasible in order to maintain image contrast which may have a negative effect on the amount of eye fatigue of radiologists. The main objective of this study is to investigate the relation between the eye fatigue and ambient light as well as to show the amount of eye fatigue at reading room (0, 50 lux) and daylight (500 lux) conditions using three different eye fatigue measurements methods (CFF, Eye Blink rate (EB), Subjective Test (ST)). In order to stimulate eye fatigue, 400 X-ray chest images with pre-marked nodules were given to the five nonradiologist subjects for evaluation under three different ambient lighting settings. Each image was present on the screen for 10 seconds; therefore one session took 66 minutes for each subject to complete and was repeated for each ambient lighting settings. Measurements were taken before and after each session. Repeated measures ANOVA for eye blink results showed that there was a trend to be significant (p=0.065) and pairwise comparison showed that the difference in respect of eye fatigue came from mainly the difference between 0 - 50 lux (p=0.061) as well as 0 - 500 lux (p=0.045). According to the Friedman statistics for subjective test, subjects felt significantly different fatigue under different ambient lighting settings (p=0.008). There was a trend to be significant correlationbetweenSTandCFFandbetweenSTandEBat0lux(p=0.065and0.068 respectively). In conclusion, eye fatigue was found to be diminishing with increasing ambient light between 0 and 50 lux and between 0 and 500 lux; however, there was no statistically significant difference between 50 and 500 lux.|Keywords : Radiology, Eye Fatigue, Critical Flicker Frequency, Eye Blink, Ambient Lighting.