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

Abstract

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.

Undertreatment of Vascular Risk Factors in Patients with Monocular Ischaemic Visual Loss

“…Modifiable risk factors such as HTN (52%), hypercholesterolaemia (36%), diabetes (15%) and current smoking (12%) were common in these patients. Our findings add to the results of previously described cohorts of both PVL and TVL, reaffirming the high incidence of risk factors among patients with ischaemic visual loss [9-14]. Similarly, for other forms of cerebrovascular disease, presentation with ischaemic visual loss is an opportunity for secondary prevention and optimisation of modifiable risk factors.…”

“…This recurrence rate is likely to be an underestimate, both due to the lack of prospective follow up and the nature of the population and organisation of services in central London; some patients were only visiting the area and could have had a further event out of region, which we may not have captured. Previous studies showed that long-term recurrence of stroke or retinal occlusion was higher in patients with diabetes, smokers, presentation with more than 3 attacks, and those with significant CAS [9-14, 18]. In contrast, we did not find any factors affecting 90-day recurrence in our cohort, perhaps due to low numbers.…”

“…Of those patients who did have carotid imaging, 14% were found to have ispilateral carotid artery stenosis ≥50%, less than previously reported [9-14, 18]; however, this is still a significant proportion of patients who are at the highest risk of further cerebrovascular events if left untreated. Patients with significant carotid artery stenosis were also more likely to present with PVL, while those with TVL were more likely to have normal ipsilateral carotid imaging, highlighting the importance of carotid disease in cerebrovascular ischaemia.…”

Blackout: Understanding transient vision loss

“…Alternatively, new-onset transient vision loss may be an early sign of a sight-threatening, and possibly life-threatening, emergency. 2,3 This review aims to guide initial management and suggest referral pathways in both of these situations.…”

“…The most common cause of monocular transient vision loss is amaurosis fugax, usually resulting from an embolic complication of an ulcerated plaque of the carotid artery. 2 In contrast, the most common cause of transient binocular vision loss is migraine. 4 It is crucial that a thorough history-taking includes an attempt at determining whether one or both eyes were affected as well as discovering the speed of onset, any precipitating factors, the speed of recovery and the presence of any residual symptoms.…”