Transient monocular blindness and the risk of vascular complications according to subtype: a prospective cohort study

Patients with transient monocular blindness (TMB) can present with many different symptoms, and diagnosis is usually based on the history alone. In this study, we assessed the risk of vascular complications according to different characteristics of TMB. We prospectively studied 341 consecutive patients with TMB. All patients were interviewed by a single investigator with a standardized questionnaire; reported symptoms were classified into predefined categories. We performed Cox regression analyses with adjustment for baseline vascular risk factors. During a mean follow-up of 4.0 years, the primary outcome event of vascular death, stroke, myocardial infarction, or retinal infarction occurred in 60 patients (annual incidence 4.4 %, 95 % confidence interval (CI) 3.4-5.7). An ipsilateral ischemic stroke occurred in 14 patients; an ipsilateral retinal infarct in six. Characteristics of TMB independently associated with subsequent vascular events were: involvement of only the peripheral part of the visual field (hazard ratio (HR) 6.5, 95 % CI 3.0-14.1), constricting onset of loss of vision (HR 3.5, 95 % CI 1.0-12.1), downward onset of loss of vision (HR 1.9, 95 % CI 1.0-3.5), upward resolution of loss of vision (HR 2.0, 95 % CI 1.0-4.0), and the occurrence of more than three attacks (HR 1.7, 95 % CI 1.0-2.9). We could not identify characteristics of TMB that predicted a low risk of vascular complications. In conclusion, careful recording the features of the attack in patients with TMB can provide important information about the risk of future vascular events.