A reader asks:

Do you have any info on the small, hand-held lighting devices that have recently been marketed? How do they compare with the 10,000 lux lamps that have been so successful?


There are two kinds of possible comparisons. One is with an ineffective placebo condition (such as dim light outside the therapeutic range, or a negative air ion generator that has been deactivated). Another type of comparison can be made with established treatments, such as 10,000 lux light therapy or antidepressant meds. We have to await completion of adequate controlled clinical trials before making any conclusion about the efficacy of hand-held devices, which greatly restrict the field of illumination.