Light injury in retina is involved with many layers of neurons. Recently, retinal ganglion cells have been regarded to be vulnerable to visible light exposure especially when they are in low bioenergetic status such as in glaucoma, ischemia and diabetic retinopathy. The present study was designed to clarify the molecular death pathway that visible light induces in RGC-5 cells and search out the critical molecular target used to develop neuroprotective drugs. RGC-5 cells were exposed under the visible light with various intensity and duration. The cell viability and death was monitored with MTT assay and PI staining. The damage of nuclear DNA caused by light was determined by plasmid assay, genome DNA assay and in situ TUNEL. The activation of nuclear enzyme PARP-1 was measured with western blot and its role in death pathway was assessed by using specific inhibitors and PARG inhibitor. The involvement of AIF was determined with western blot, immunofluenrescent staining and its inhibitor. The calcium influx was examined by fura-2 assay and calcium channel blocker. The visible light induced RGC-5 cell death in a time and intensity manner. The light exposure was able to directly cause the double strands breaks and damage in nuclear DNA. As a nuclear enzyme, PARP-1 was remarkably activated and its specific inhibitors showed significantly neuroprotective effect. AIF, a down stream factor of PARP-1, was also involved in light-induced death pathway and massive calcium influx was detected after light exposure. Both AIF inhibitor and calcium channel blocker partially protected cells against light injury. These results suggest that visible light exposure can be a direct factor to cause nuclear DNA damage which in turn activates PARP-1. Yet the over-activation of nuclear enzyme PARP-1 is the critical molecular step to finally induce cell death, so blocking PARP-1 may have therapeutic effects, rescuing the retinal ganglion cells from light damage.