The effect of visual stimuli on pain threshold and tolerance

For many hospital patients, the experience brings pain and anxiety. Unfamiliar surroundings, various diagnostic and therapeutic procedures, and the sight and sounds of medical procedures exacerbate pain and anxiety. To block off the anxiety-inducing sights and sounds of hospital surroundings and create a pleasing environment, the therapeutic potential of visual stimulation as a nursing intervention was investigated. In a randomized, controlled, cross-over study, pain was produced by a modified tourniquet technique in 46 healthy volunteers. Subjects were randomly allocated to two groups (Group V and Group B) with subsequent cross-over. Those in Group V watched a soundless video display of natural scenery during tourniquet inflation, whereas in Group B subjects watched a static blank screen. Pain threshold was defined as the time when subjects reported the first detectable pain, whereas pain tolerance was the time the pain was reported to be intolerable and deflation of the tourniquet was requested. With the use of visual stimuli, there was a significant increase in pain threshold (P < 0.05) and pain tolerance (P < 0.01). Gender and the sequence of visual stimuli did not have any significant effect on pain threshold and pain tolerance. Further studies specifically addressing level of anxiety and physiological data correlated with pain scores and visual stimuli are needed. The findings have implications for nurses and other healthcare professionals to use various visual stimuli as positive adjuncts to other methods of pain relief and for different pain conditions in clinical areas.