Visual signs and symptoms of multiple system atrophy

Abstract

Multiple system atrophy (MSA) is a rare movement disorder and a member of the ‘parkinsonian syndromes’, which also include Parkinson's disease (PD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB) and corticobasal degeneration (CBD). Multiple system atrophy is a complex syndrome, in which patients exhibit a variety of signs and symptoms, including parkinsonism, ataxia and autonomic dysfunction. It can be difficult to separate MSA from the other parkinsonian syndromes but if ocular signs and symptoms are present, they may aid differential diagnosis. Typical ocular features of MSA include blepharospasm, excessive square‐wave jerks, mild to moderate hypometria of saccades, impaired vestibular‐ocular reflex (VOR), nystagmus and impaired event‐related evoked potentials. Less typical features include slowing of saccadic eye movements, the presence of vertical gaze palsy, visual hallucinations and an impaired electroretinogram (ERG). Aspects of primary vision such as visual acuity, colour vision or visual fields are usually unaffected. Management of the disease to deal with problems of walking, movement, daily tasks and speech problems is important in MSA. Optometrists can work in collaboration with the patient and health‐care providers to identify and manage the patient's visual deficits. A more specific role for the optometrist is to correct vision to prevent falls and to monitor the anterior eye to prevent dry eye and control blepharospasm.

Oculo‐visual abnormalities in Parkinson's disease: Possible value as biomarkers

“…Second, an outstanding question is to what extent ocular manifestations of PD can be differentiated from other parkinsonian syndromes, normal aging, and other neurodegenerative diseases. In a comparison of PD and MSA, corticobasal degeneration, progressive supranuclear palsy, and Lewy body dementia, Armstrong suggested predominantly differences in complex visual functions, such as visuospatial dysfunction, visual hallucinations, and event‐evoked potentials . Differences in the eye between PD and MSA have been reported, including RNFL thinning with preferential loss of M‐type RGCs in the MSA retina, with preservation of visual acuity and color vision in MSA when compared with PD …”

Visual signs and symptoms of corticobasal degeneration

“…The major visual signs and symptoms described in CBD are summarised in Table . Caution is required in interpreting these data as: vision has been studied less frequently in CBD than in other parkinsonian disorders; studies rely on a clinical diagnosis of CBS, which can be difficult; and CBD is rare and therefore, sample sizes in clinical studies are often limited. …”

“…There are few data concerning changes in primary vision in CBD such as visual acuity. Nevertheless, patients with a parkinsonian syndrome often complain of poor vision as the disease progresses and such changes could be present in CBD . Nevertheless, in patients with CBD, among whom difficulties involving visuospatial tasks or in reading ability have been reported, the patients denied that they had a significant visual loss .…”

“…Second, CBD is characterised by a cellular pathology consisting of abnormal cellular aggregations of the microtubule‐associated protein tau and in this respect is similar to Alzheimer's disease and progressive supranuclear palsy (PSP) . Third, CBD is included within the ‘parkinsonian’ group of disorders, which includes Parkinson's disease, PSP, dementia with Lewy bodies (DLB) and multiple system atrophy …”

“…Visual signs and symptoms are frequently present in parkinsonian syndromes . Corticobasal degeneration can be difficult to distinguish from the other parkinsonian syndromes but if ocular signs and symptoms occur they can aid clinical diagnosis.…”