Clinical assessment, investigation, diagnosis and initial management of cerebral visual impairment: a consensus practice guide

Abstract

Cerebral Visual Impairment (CVI) is a common condition in the UK. Patients with conditions associated with CVI are frequently seen in paediatric ophthalmology clinics offering eye care professionals an opportunity to identify children proactively. In most cases CVI occurs as part of a neurodevelopmental condition or as a feature of multiple and complex disabilities. However, CVI can also be seen in children with apparently typical development. In some cases, high contrast visual acuity is normal and in other cases severely impaired. As such, identification of CVI requires evaluation of aspects of visual performance beyond high contrast acuity and consideration that visual function of those with CVI may fluctuate. Few paediatric ophthalmologists have received formal training in CVI. The detection and diagnosis of CVI varies across the UK and patients report hugely different experiences. A diagnosis of CVI is made based on professional clinical judgement and it is recognised that individual perspectives and local practice in the specific methodologies of assessment will vary. A systematic review and survey of professionals is underway to attempt to reach agreement on diagnostic criteria. Nonetheless, established pathways and published protocols can offer guidance on how a paediatric ophthalmology service can approach assessment of the child with suspected CVI. The purpose of this paper is to present a summary of research and clinical practice methods for detecting and diagnosing CVI in a paediatric ophthalmology outpatient setting. It represents current understanding of the topic and acknowledges the evolving nature of both practice and the evidence-base. A rapid literature review was undertaken to identify articles relating to clinical investigation of children with CVI. A focus group of QTVI and subject matter experts from sight loss charities was undertaken to address areas which were not covered by the literature review.

Validation of the Austin Assessment: A screening tool for cerebral visual impairment related visual issues

“…The analysis of the vision assessments on the 23 children who warranted further visual testing identified that 17 out of 23 had a verifiable reason or clinical findings that would make a result that was outside the normative range in the Austin Assessment a reliable true positive, and not just for CVI related visual issues (Table 3). Using the criteria outlined by Pilling, Allen [8], five children were identified as CVI being highly likely (meeting all three criteria),…”

“…The children that do get referred for an ophthalmic assessment for suspicion of CVI are generally those with low visual acuity and a known medical history that is suggestive of CVI. However, as highlighted by Pilling, Allen [8] while a known medical risk factor can be an indicator for CVI, not all children with CVI will present with a known medical event that resulted in their visual issues. This is supported by Chandna, Ghahghaei [18] who highlight that normal visual acuity and absence or presence of neuroimaging findings no longer excludes a diagnosis of CVI.…”

“…In addition to these five areas, McConnell, Saunders [7] have also shown that other areas assessed in the diagnostic process include visual behaviors and direct observation, visual perception tests, ocular movement and posture assessments, IQ assessments, clinical electrophysiology, and neurodevelopmental tests. Further to this, Pilling, Allen [8] have recently outlined a checklist to help guide practitioners to decide whether CVI is a possibility that requires further CVI specific assessment. They outline that CVI may be present if two or three of the following criteria are met: 1) presence of risk factor(s), 2) reported or observed atypical visual behaviors, and 3) verifiable visual dysfunction on examination.…”

“…They outline that CVI may be present if two or three of the following criteria are met: 1) presence of risk factor(s), 2) reported or observed atypical visual behaviors, and 3) verifiable visual dysfunction on examination. The authors also outline that CVI is highly likely to be present if all three criteria are met [8].…”

Deficits in Face Recognition and Consequent Quality-of-Life Factors in Individuals with Cerebral Visual Impairment

“…CVI is an umbrella term encompassing a variety of visual dysfunctions as a consequence of brain injury, malformation, and/or genetic disorders [ 15 ]. Generally speaking, children with CVI may be placed into one of four profiles based on the severity of functional impact [ 16 ]; in each profile, the extent of the visual dysfunctions are beyond what may be expected due to any potentially co-occurring ocular visual impairment [ 17 ]. While many individuals with CVI demonstrate dorsal stream dysfunctions, such as impairments in visual attention and motion perception [ 18 , 19 , 20 ], many may also exhibit ventral stream dysfunctions.…”