Prothrombotic and vascular risk factors in nonarteritic anterior ischemic optic neuropathy

Abstract

In the paper entitled, “Analysis of prothrombotic and vascular risk factors in patients with nonarteritic anterior ischemic optic neuropathy [NAION]” (Ophthalmology 1999;106:739–42), Salomon et al reported that NAION was not found to be associated with acquired thrombophilic risk factors (e.g., protein C, protein S, antithrombin III, lupus anticoagulant, and prothrombotic polymorphisms). Although there have been a few scattered reports of the presence of these factors in patients with NAION in the literature, this study was the first systematic analysis of these potential risk factors in NAION.It has been our practice not to order these studies for typical NAION, and I believe that the elegant work of the authors supports this recommendation strongly. We have, however, performed these laboratory studies in the following patients: 1) young (less than 45 years of age) patients with NAION without vasculopathic risk factor (e.g., hypertension, diabetes, elevated cholesterol, or smoking); 2) NAION without a small cup to disk ratio (“the disk at risk”) in the fellow eye; 3) bilateral simultaneous NAION; 4) recurrent NAION in the same eye; and 5) NAION in a patient with a previous history or family history of recurrent thrombotic events. In this study, patients with NAION younger than age 50 did not differ significantly from patients older than age 50 with respect to any of the factors studied. In the paper entitled, “Analysis of prothrombotic and vascular risk factors in patients with nonarteritic anterior ischemic optic neuropathy [NAION]” (Ophthalmology 1999;106:739–42), Salomon et al reported that NAION was not found to be associated with acquired thrombophilic risk factors (e.g., protein C, protein S, antithrombin III, lupus anticoagulant, and prothrombotic polymorphisms). Although there have been a few scattered reports of the presence of these factors in patients with NAION in the literature, this study was the first systematic analysis of these potential risk factors in NAION. It has been our practice not to order these studies for typical NAION, and I believe that the elegant work of the authors supports this recommendation strongly. We have, however, performed these laboratory studies in the following patients: 1) young (less than 45 years of age) patients with NAION without vasculopathic risk factor (e.g., hypertension, diabetes, elevated cholesterol, or smoking); 2) NAION without a small cup to disk ratio (“the disk at risk”) in the fellow eye; 3) bilateral simultaneous NAION; 4) recurrent NAION in the same eye; and 5) NAION in a patient with a previous history or family history of recurrent thrombotic events. In this study, patients with NAION younger than age 50 did not differ significantly from patients older than age 50 with respect to any of the factors studied.