Red light has been shown to provide neuroprotective effects. Axotomizing the optic nerve initiates retinal ganglion cell (RGC) degeneration, and an early marker of this is dendropathy. We demonstrate the ability of 670 nm light to partially prevent ex vivo dendropathy in the mouse retina. The area under the Sholl curve, the peak of the Sholl curve, dendritic length and dendritic field area showed statistically significant reductions after 16 h by 40.56% (P < 0.008), 33.9% (P < 0.007), 45.43% (P < 0.006) and 44.23% (P < 0.019), respectively, in sham-treated retinae. Such statistically significant reductions were not seen in red light-treated retinae.