The age and visual health of the worker. All tasks on the farm will not require the same amount of illumination nor the same type of illumination source. Avoid sharp contrasts, especially for work in animal areas where shadows can cause animals to spook. Glare and flicker Glare occurs when the field of view contains areas of high brightness that interfere with vision of the normal task. Limited amounts of glare may cause only annoyance, but unexpected bright glare may be a hazard if a worker is temporarily blinded.
Flicker is annoying, especially when noticed in the peripheral line of vision.
Fluorescent tubes can cause noticeable flicker. Flicker may also be more noticeable with bluer lamps than with redder ones. Besides being annoying, flicker can cause headaches. Discharge lamps such as florescent lights can pose a serious danger when serving as the source of light in areas where rotating or reciprocating machinery is used. The stroboscopic effect occurs when the machinery rotates but appears to be slower moving.