Nonarteritic Anterior Ischemic Optic Neuropathy: Role of Nocturnal Arterial Hypotension

We believe the article by Landau et al 1 has several shortcomings. Landau et al argue that nocturnal arterial hypotension plays no role in the development of anterior ischemic optic neuropathy (AION), while our studies suggest that it is an important precipitating factor for AION. 2 Many risk factors contribute to AION. Some are predisposing factors, and others are precipitating factors. 2,3 When an optic nerve head (ONH) has been rendered vulnerable to ischemia by various predisposing factors, nocturnal hypotension may act as the "last straw" to produce ischemia and AION. 2,3 A similar or even greater degree of nocturnal arterial hypotension in a healthy ONH would have no effect at all. Thus, nocturnal arterial hypotension must be placed in the overall context of the disease process and not in isolation (as Landau et al did). Our disagreements are as follows: The authors state that "The patient with AION typically