Functional visual loss: a systematic review and meta-analysis of epidemiology, prognosis and treatment

Functional visual loss is a common issue in neuro-ophthalmology settings. There are many studies focused on diagnosis, but there is limited literature on associated epidemiology, phenomenology, prognosis and treatment. We carried out the first systematic review and meta-analysis assessing these domains. We systematically reviewed PubMed from 1951 for studies reporting clinical data on adults and children with functional visual loss. Data on variables relevant to epidemiology, phenomenology, comorbidity, risk factors, prognosis and treatment were extracted. Random effects meta-analyses were performed where appropriate. Forty-four studies of functional visual loss (n = 2284, 67% female) were included. The pooled median age was 43 years (IQR 12.5-43 years). Common associations included facial/ocular trauma (19%, n = 288), ocular comorbidity (25%, n = 470), headache (39%, n = 124) and other functional symptom/disorder (10-29%). Good quality data on psychiatric comorbidity and adverse childhood experience were unavailable. Prognosis data (n = 1019, 13 studies) were heterogeneous, but outcome appeared more favourable in paediatric studies. Most studies did not distinguish between symptomatic visual loss and functional visual signs which are asymptomatic (such as spiralled fields) or disproportionate to symptoms (such as severe acuity loss in someone with minor visual symptoms). There are very limited data on treatment. This systematic review highlights some basic epidemiological data and relevant aetiological factors in functional visual loss but also the significant gaps that must be addressed to improve care for this disabling condition.