A recent paper by Willis et al. [1] casts doubts on the conclusions drawn by Romeo et al. (see Post 1 of this thread.)

Willis et al. write:
"Critical analysis of recent research suggesting that light pollution causes Parkinson's disease (PD) reveals that such a hypothesis is unsustainable in the context of therapeutic use of light in treating various neuropsychiatric conditions. Reinterpretation of their findings suggests that retinal damage caused by prolonged light exposure may have contributed to the observed enhancement of experimental PD."

Reference

[1] "Parkinson's Disease, Lights and Melanocytes: Looking Beyond the Retina"
Gregory L. Willis, Cleo Moore & Stuart Maxwell Armstrong
Nature Scientific Reports, January 2014
http://www.nature.com/srep/2014/1401...srep03921.html

John