Human sensitivity to short-wavelength light in non-image-forming vision: toward a mechanistic understanding of the impact of blue light on sleep and circadian rhythms


  • Dr Manuel Spitschan

    University of Oxford, United Kingdom

Project summary

Many studies in chronobiology and sleep research that examine the effects of light on the suppression of melatonin and circadian photoentrainment have exclusively examined men or have only included women with a natural menstrual cycle. Women who use hormonal contraceptives have been excluded from studies based on evidence that melatonin production may be modulated by the menstrual cycle. 

We will develop a systematic survey of sex representation in research studies on the non-visual effects of light. We will use a pre-registered systematic review, a well-defined database search strategy and standardised information extraction methods to investigate recruitment in these studies. We will look at sample size and the proportion of women and their hormonal status. We will also develop an open-access toolkit for researchers on addressing sex biases when recruiting participants for sleep studies. 

Our research will increase our knowledge of sex-based biases in the scientific literature on the non-visual effects of light.