The mechanism of action of ECHO in this patient with Stargardt’s disease is not yet known. Our hypothesis is that dilute ECHO makes ACh more available to diseased neuroreceptor populations across the retina. Increased ACh levels may amplify the synaptic potential of the surviving photoreceptors and ganglion cells, making it possible for these reduced populations to achieve threshold and resume the propagation of visual information to the brain. This effect would parallel previously described mechanisms of drug action in other neurological diseases, such as Parkinsonism, Alzheimer’s Disease and Clinical Depression.