Tumor necrosis factor alpha (TNF-alpha) is a cytokine produced and released by activated microglia [28] that regulates the expression of neurotrophins and their receptors in glial cells [29] and monocytes [30], modulates neurite outgrowth [31,32,33], and acts as a neuroprotective agent in models of retinal ischemia [34]. This evidence concerns the gene TNF and retinal ischemia.