In cases of RP, Cellini and coworkers have reported that a general increase in plasma levels of ET-1 elicits vasoconstriction both systemically and locally in the eye, causing retinal and choroidal hemodynamic impairment involving both ophthalmic artery and posterior ciliary arteries [2, 5, 6, 58, 59]. Here, EDN1 is linked to retinitis pigmentosa 1.