Cognitive visual dysfunction

Relationship between visual function and cognitive function in the elderly: A cross-sectional observational study

It has been suggested that functional visual acuity (VA) testing may be able to measure both the visual performance and cognitive ability needed for driving and help to reduce the number of road traffic accidents. The aim of this study was to investigate the relationship between visual ability and cognitive function in healthy elderly subjects. The study included 34 eyes with a decimal best-corrected visual acuity (VA) ≥1.0 in 34 subjects (16 men, 18 women; mean age 72.7 ± 6.1 [range, 61-83] years) with the same type of monofocal intraocular lens implant. Using the score on the Japanese version of the Mini-Mental State Examination (MMSE) questionnaire, the subjects were divided into a mild cognitive impairment (MCI) group (score <28) and a normal cognition (NC) group (score ≥28). Visual ability was evaluated by functional VA testing. Functional VA was significantly lower in the MCI group (n = 10) than in the NC group (n = 24; P<0.02). There was no significant difference in best-corrected VA between the two groups. High correlations were found between the MMSE score and the logMAR functional VA (r = -0.36, P = 0.04), standard deviation of functional VA (r = -0.39, P = 0.02), and the visual maintenance ratio (r = 0.34, P = 0.048). In summary, despite a good best-corrected VA, deterioration in visual ability was detected in elderly individuals with MCI when measured by the functional VA test. Functional VA could be used to evaluate the integrated visual ability associated with age-related cognitive decline and have applications that help to reduce the disproportionately high rate of road traffic accidents in the elderly.

Relationship between brain structure and Cerebral Visual Impairment in children with Cerebral Palsy: A systematic review

BACKGROUND

Cerebral Visual Impairment (CVI) is very common yet often unrecognised visual dysfunction in children with Cerebral Palsy (CP). Magnetic Resonance Imaging (MRI) is the diagnostic tool in the investigation of brain lesions in children with CP and CVI.

AIM

The aim of this systematic review is to evaluate the relationship between brain structure and CVI, as determined by MRI in children with CP.

METHODS AND PROCEDURES

A comprehensive search of 5 database (PubMed, EMBASE, SCOPUS, CINAHL and Cochrane Database) was undertaken up until June 2019. The PRISMA checklist was then utilised to report on the process of selecting eligible papers. A total of 30 observational studies met the full inclusion criteria. Further, STROBE checklist was employed to report on the observational studies.

OUTCOMES AND RESULTS

Periventricular leucomalacia on MRI was found to have a strong association with CVI in all 30 studies. Only 13 (43 %) studies described dorsal and/ ventral stream dysfunction. There was ambiguity in the definition of CVI.

CONCLUSIONS AND IMPLICATIONS

The overall level of evidence correlating different patterns of CVI and CP (based on GMFCS, motor type and distribution) and MRI was low. Further studies utilising advances in MRI are needed to understand brain reorganisation and patterns of CVI and suggest rehabilitation therapy inclusive of vision.

Uniplanar Nystagmus Associated with Perceptual and Cognitive Visual Dysfunction due to Presumed Focal Ischemic Occipital Cortical Atrophy: A Missed Diagnosis and New Observation

Uniplanar nystagmus has been described in relation to pathology of the brain stem, retina, optic nerve, sensory visual deprivation, periventricular leucomalacia, and drug toxicity. This paper describes a case of uniplanar nystagmus associated with features of higher visual dysfunction and a presumed focal insult to the occipital lobes following an episode of neonatal apnea.

Neuro-ophthalmological disorders in cerebral palsy: ophthalmological, oculomotor, and visual aspects

AIM

Cerebral visual impairment (CVI) is a disorder caused by damage to the retrogeniculate visual pathways. Cerebral palsy (CP) and CVI share a common origin: 60 to 70% of children with CP also have CVI. We set out to describe visual dysfunction in children with CP. A further aim was to establish whether different types of CP are associated with different patterns of visual involvement.

METHODS

A total of 129 patients (54 females, 75 males; mean age 4 y 6 mo, SD 3 y 5 mo; range 3 mo-15 y) with CP (51 with diplegia, 61 with tetraplegia, and 17 with hemiplegia; 62 [48%] of participants were able to walk) and CVI enrolled at the Centre of Child Neuro-ophthalmology (at the Department of Child Neurology and Psychiatry, IRCCS 'C. Mondino Institute of Neurology', University of Pavia) underwent an assessment protocol including neurological examination, developmental and/or cognitive assessment, neuro-ophthalmological evaluation including ophthalmological assessment, evaluation of visual acuity, contrast sensitivity, optokinetic nystagmus, visual field and stereopsis, and neuroradiological investigations.

RESULTS

Visual dysfunction in diplegia was characterized mainly by refractive errors (75% of patients), strabismus (90%), abnormal saccadic movements (86%), and reduced visual acuity (82%). The participants with hemiplegia showed strabismus (71%) and refractive errors (88%); oculomotor involvement was less frequent (59%). This group had the largest percentage of patients with altered visual field (64%). Children with tetraplegia showed a severe neuro-ophthalmological profile, characterized by ocular abnormalities (98%), oculomotor dysfunction (100%), and reduced visual acuity (98%).

INTERPRETATION

Neuro-ophthalmological disorders are one of the main symptoms in CP. Each clinical type of CP is associated with a distinct neuro-ophthalmological profile. Early and careful neuro-ophthalmological assessment of children with CP is essential for an accurate diagnosis and for personalized rehabilitation.

Visual assessment in children with cerebral palsy: implementation of a functional questionnaire

AIM

The aim of this study was to evaluate an interdisciplinary visual assessment for multiply challenged children diagnosed with cerebral palsy (CP).

METHOD

A comprehensive ophthalmological assessment together with a visual classification scale (VCS) and a questionnaire evaluating daily visual function were completed regarding 77 children (41 females, 36 males; age range 3-20y; mean age 8 y 3 mo [SD 4 y 3 mo]; Gross Motor Function Classification System [GMFCS] level V; Manual Ability Classification System level V) who were diagnosed with CP (79.2% spastic quadriplegia, 6.5% athetoid quadriplegia, 10.4% mixed type, 3.9% hemiplegia). All participants had severe to profound motor and intellectual disability and an inability to communicate consistently through either verbal or assisted communication. The interrater and test-retest reliability of the questionnaire and its validity in comparison with the VCS were examined. In addition, the contribution of ophthalmological testing in predicting daily visual function was assessed.

RESULTS

The ophthalmological examination revealed three diagnostic subgroups: a group with cerebral visual impairment (CVI), a group with optic atrophy, and a group without visual impairment. The questionnaire was found to have high values of interrater reliability (interclass correlation coefficient [ICC]=0.873; 95% confidence interval [CI] 0.762-0.935) and test-retest reliability (ICC=0.988; 95% CI 0.964-0.996). Validity was established for the questionnaire factors: task-orientated visual function (r=0.802; 95% CI 0.669-0.885) and basic visual skills (r=0.691; 95% CI 0.504-0.816). The questionnaire provided information about daily visual performance not available from one-time ophthalmological testing, particularly for participants diagnosed with CVI. The visual performance scale significantly predicted daily visual function for all groups.

INTERPRETATION

This study highlights the benefits of implementing a diagnostic performance scale as well as a reliable functional questionnaire to achieve a precise visual assessment of children with severe neurological impairment.

Temporal visual field defects are associated with monocular inattention in chiasmal pathology

PURPOSE

Chiasmal lesions have been shown to give rise occasionally to uni-ocular temporal inattention, which cannot be compensated for by volitional eye movement. This article describes the assessments of 46 such patients with chiasmal pathology. It aims to determine the clinical spectrum of this disorder, including interference with reading.

METHODS

Retrospective consecutive observational clinical case study over a 7-year period comprising 46 patients with chiasmal field loss of varying degrees. Observation of reading behaviour during monocular visual acuity testing ascertained from consecutive patients who appeared unable to read optotypes on the temporal side of the chart. Visual fields were evaluated by kinetic (Goldmann) and static (Octopus) techniques. Five patients who clearly manifested this condition are presented in more detail. The results of visual field testing were related to absence or presence of uni-ocular visual inattentive behaviour for distance visual acuity testing and/or reading printed text.

RESULTS

Despite normal eye movements, the 46 patients making up the clinical series perceived only optotypes in the nasal part of the chart, in one eye or in both, when tested for each eye in turn. The temporal optotypes were ignored, and this behaviour persisted despite instruction to search for any additional letters temporal to those, which had been seen. This phenomenon of unilateral visual inattention held for both eyes in 18 and was unilateral in the remaining 28 patients. Partial or full reversibility after treatment was recorded in 21 of the 39 for whom reliable follow-up data were available. Reading a text was affected in 24 individuals, and permanently so in six.

CONCLUSION

A neglect-like spatial unawareness and a lack of cognitive compensation for varying degrees of temporal visual field loss were present in all the patients observed. Not only is visual field loss a feature of chiasmal pathology, but the higher visual function of affording attention within the temporal visual field by means of using conscious thought to invoke appropriate compensatory eye movement was also absent. This suggests the possibility of 'trans-synaptic dysfunction' caused by loss of visual input to higher visual centres. When inattention to the temporal side is manifest on monocular visual testing it should raise the suspicion of chiasmal pathology.

Spectrum of visual disorders in children with cerebral visual impairment

Cerebral visual impairment is a visual function deficit caused by damage to the retrogeniculate visual pathways in the absence of any major ocular disease. It is the main visual deficit in children in the developed world. Preperinatal hypoxic-ischemic damage is the most frequent cause of cerebral visual impairment, but the etiology is variable. The authors set out to evaluate the presence of visual disorders not attributable to any major ocular pathology in a sample of children with central nervous system disease and to describe the clinical picture of cerebral visual impairment in this cohort. One hundred twenty-one patients with central nervous system damage and visual impairment underwent a protocol developed at the authors' center that included neurologic, neurophthalmologic, and neuroradiologic assessments (brain magnetic resonance imaging). Reduced visual acuity was found in 105 of 121 patients, reduced contrast sensitivity in 58, abnormal optokinetic nystagmus in 88, and visual field deficit in 7. Fixation was altered in 58 patients, smooth pursuit in 95, and saccadic movements in 41. Strabismus was present in 88 patients, and abnormal ocular movements were found in 43 patients. Of the 27 patients in whom they could be assessed, visual-perceptual abilities were found to be impaired in 24. Fundus oculi abnormalities and refractive errors were frequently associated findings. This study confirms that the clinical expression of cerebral visual impairment can be variable and that, in addition to already well-documented symptoms (such as reduced visual acuity, visual field deficits, reduced contrast sensitivity), the clinical picture can also be characterized by oculomotor or visual-cognitive disorders. Cerebral visual impairment is often associated with ophthalmologic abnormalities, and these should be carefully sought. Early and careful assessment, taking into account both the neurophthalmologic and the ophthalmologic aspects, is essential for a correct diagnosis and the development of personalized rehabilitation programs.

A survey of visual impairment in children attending the Royal Blind School, Edinburgh using the WHO childhood visual impairment database

PURPOSE

To assess the aetiology and changing patterns of childhood blindness in one school for the blind in the UK and to assess the use of the World Health Organisation Prevention of Blindness (WHO/PBL) methodology and reporting form in a developed country.

METHODS

One hundred and seven children in one school for the blind and visually impaired in Edinburgh were examined using the WHO/PBL childhood blindness assessment form.

RESULTS

Of the 107 children examined, 87 (81%) were blind or severely visually impaired (corrected visual acuity of <6/60 (20/200) in the better eye). Perinatal related blindness (40%), hereditary disease (26%) and developmental factors (26%) formed the three largest aetiological categories.

CONCLUSION

The pattern of childhood blindness seen in this study was similar to reports from other developed countries. The WHO/PBL reporting form allows detailed comparisons between countries and over time. Additional fields for more detailed reporting of cerebral visual impairment and associated handicaps would increase the usefulness of the WHO/PBL form for population-based studies and for use in developed countries.

Development of a quantitative method to measure vision in children with chronic cortical visual impairment

PURPOSE

Cortical visual impairment (CVI) is the most common cause of bilateral vision impairment in children in Western countries. Better quantitative tools for measuring vision are needed to assess these children, to allow measurement of their visual deficit, and to monitor their response to treatment and rehabilitation. The author performed a series of experiments to assess the use of the sweep visual evoked potential (VEP) as a quantitative tool for measuring vision in CVI.

METHODS

The first experiment was a reliability measure (test/retest) of VEP grating acuity thresholds of 23 children with CVI. To validate the VEP procedure, VEP grating acuity was compared to a clinical measure of vision, the Huo scale, and to a psychophysical measure of vision, the Teller Acuity Card procedure. Finally, the sweep VEP was tested as a tool for defining optimal luminance conditions for grating acuity in 13 children with CVI, by measuring grating thresholds under 2 different luminance conditions: 50 and 100 candela per square meter (cd/m2).

RESULTS

Retest thresholds were similar to original thresholds (r2 = 0.662; P = .003, 1-tailed t test). Grating VEP measures correlate significantly with the clinical index (r2 = 0.63; P = .00004). Teller acuity measurements are also similar to VEP measures in children (r2 = 0.64; P = .0005) but show lower acuities compared to the VEP for children with particularly low vision. Finally, 3 of 13 children tested under 2 background luminance conditions showed paradoxical improvement in grating threshold with dimmer luminance.

CONCLUSIONS

The sweep VEP tool is a reliable and valid means for measuring grating acuity in children with CVI. The tool also shows promise as a means of determining the optimal visual environment for children with CVI.

Cognitive visual dysfunction in a child with cerebral damage

Visual impairment as a sequel to cortical damage can be associated with complex disorders in cognitive visual function. Such dysfunction can be difficult to diagnose with certainty, particularly in children, owing to the child's problems of awareness and communication. The authors describe the case of a 13-year-old girl whose cerebral damage is apparently accompanied by complex cognitive visual disorders. Though she has a good binocular visual acuity, she cannot see rapidly moving objects. She has difficulties with orientation, recognising faces and cognitive depth perception. Despite an absence of detailed psychometric testing, a clinical diagnostic approach such as that used in this case, based on a CT scan and careful history-taking and observation, may be helpful in planning educational strategies.

Cortical visual dysfunction in children: a clinical study

Damage to the cerebral cortex was responsible for impairment in vision in 90 of 130 consecutive children referred to the Vision Assessment Clinic in Glasgow. Cortical blindness was seen in 16 children. Only 2 were mobile, but both showed evidence of navigational blind-sight. Cortical visual impairment, in which it was possible to estimate visual acuity but generalised severe brain damage precluded estimation of cognitive visual function, was observed in 9 children. Complex disorders of cognitive vision were seen in 20 children. These could be divided into five categories and involved impairment of: (1) recognition, (2) orientation, (3) depth perception, (4) perception of movement and (5) simultaneous perception. These disorders were observed in a variety of combinations. The remaining children showed evidence of reduced visual acuity and/ or visual field loss, but without detectable disorders of congnitive visual function. Early recognition of disorders of cognitive vision is required if active training and remediation are to be implemented.

Assessment of visual acuity in multiply handicapped children

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