Research on Subjective Fatigue of Sonographers and Illumination in the Laboratory

Abstract

An ultrasonography requires a sonographer to work in a dark room while viewing images on a monitor. This can result in eye strain and subjective fatigue. Furthermore, sonographers often are forced to work in an unnatural posture and they are suffering from subjective fatigue in their arms and shoulders as well. This report adresses the correlation between operator's subjective fatigue and illuminance of ultrasonography room. The following brightness parameters were measured at five ultrasonography facilities ambient illuminance of the room,and ultrasonograph monitor surface illuminance and luminance. The subjective fatigue was measured by testing visual acuity of 29 sonographers working at above mentioned menitioned facilities, and interviewing them subjective symptoms. A difference in illuminance of 0.05～50 lx was observed among the rooms. Two facilities used darkened rooms, whereas three used down-lighting, thereby allowing comparison between bright and dark rooms. Sonographers appeal their physical and eye fatigue more often in the evening than morning, and it is considered that the performing of ultrasonography itself causes eye strain. Sonographers were found to have increased complaints in dark rooms. It is necessary to establish the criteria for lighting in ultrasonography rooms and the conditions for reducing the sonographer's subjective fatigue.