Lack of sleep contributes to a host of medical and psychiatric illnesses, such as obesity, diabetes, mood disorders and ADHD. Blue light from electronic devices may suppress melatonin and interfere with sleep. According to one study, "Ari Shechter, Elijah Wookhyun Kim, Marie-Pierre St-Onge, and Andrew Westwood, "Blocking Nocturnal Blue Light for Insomnia: A Randomized Controlled Trial," Journal of Psychiatric Research 96, (January 2018): 196-202, doi:10.1016/j/psychires.2017.10.015), blocking blue light with amber glasses two hours before sleep, subjective total sleep time, overall quality and soundness of sleep improved, and improved sleep in individuals with insomnia.