Melatonin decreases the amplitude of the b-wave of the human electroretinogram.

In a double-blind placebo crossover study of 13 healthy volunteers, the pineal hormone melatonin (10 mg) was given at 4 pm, and the electroretinogram measured under conditions of dark and light adaptation. A significant diminution of b-wave amplitude was found under both photopic (delta = 5.4 microV, p < 0.05) and scotopic conditions (delta = 7.4 microV, p < 0.01). These data indicate that melatonin may transduce the dark signal at the level of the retina as well as the pineal. Acute administration of melatonin decreases sensitivity to light.

RCT Entities:   Population Interventions Outcomes