Study reference

Study characteristics

Patient characteristics ²

Intervention (I)

Comparison / control I ³

Follow-up

Outcome measures and effect size ⁴

Comments

Bosch, 2014

Type of study: cross-sectional study

Setting: tertiary care institute for the visually impaired

Country: The Netherlands

Source of funding: This work has been supported by grants from Stichting ODAS that contributed through UitZicht, Dutch Organization for Health Research and Development (917-86-319 to BBAdV), Dutch Brain Foundation (to BBAdV) and the Vereniging Bartiméus-Sonneheerdt (5781251).

Inclusion criteria:

Diagnosis of CVI; and a first visit over a 10 years period between 1-1-2002 and 1-1-2012 and low vision, defined as a visual acuity of ≤0.3 or <1.6 cycles/cm at 55 cm or a visual field radius of ≤30° degrees

Exclusion criteria: a second ocular diagnosis causing low vision, such as cataract or retinopathy of prematurity. Primary (hereditary) optic atrophy or congenital idiopathic nystagmus were excluded based on the history and results during ocular examination by the ophthalmologist. Bilateral amblyopia was excluded as refraction was measured and corrected if necessary.

N total at baseline: 309

Important prognostic factors²:

Age first examination: 36 (4 months-45 years)

Age most recent examination: 53 (5 months-45 years)

Sex: 55 % M

Describe intervention (treatment/procedure/test):

-

Describe control (treatment/procedure/test):-

Length of follow-up:

-

Outcome measures and effect size (include 95%CI and p-value if available):

309 individuals with low vision fulfilled the criteria for CVI

In 32% (71/221) the gestational age was below 37 weeks, of which two-thirds were born before 35 weeks. In 67% of the cohort a MRI-scan was performed, which was reported normal in only 14% (28/206). Brain anomalies were either caused by a disturbance in the developmental process (e.g. lissencephaly, cortical dysplasia) and white matter disease (e.g. hypomyelinisation) or acquired (e.g. periventricular leucomalacia (PVL), stroke).

It was possible to identify one or more possible causes for CVI in 60% of the cohort. In 23% there was evidence of severe perinatal problems, such as ospitalc or infarctions, PVL or post-partum reanimation. In 11% exogenous factors led to brain damage and CVI, such as meningitis or encephalitis, a diabetic coma, or a complication during an operation. Hydrocephalus was present in 6% and West syndrome in 9% of the cohort. A genetic diagnosis was reported in 21%, of which 50% had a proven chromosomal aberration. In half of the persons with a genetic syndrome other factors, such as West syndrome or stroke, may have contributed to the CVI. In the other half the CVI might be associated with the genetic syndrome.

CVI was diagnosed when there was no other ocular diagnosis which could explain the visual impairment or visual field defect, and/or typical features such as poor fixation or crowding, and/or CVI were found at neuropsychological investigation.

Chen, 1992

Type of study: cohort

Setting: Albany medical center hospital

Country: USA

Source of funding: partly by a grant SO7RR05394-28 from the Biomedical Research Support Grant Program, Division of Research Resources , NIH; and by an unrestricted grant from Research to prevent blindness, New York, New York

Inclusion criteria: a review of the records showed 30 infants who were between 6 and 12 months old who had sustained CVI when they were initially examined between 1982 and 1990

Exclusion criteria: transient cortical visual impairment,

N total at baseline: 30

Important prognostic factors²:

For example

age ± SD:

I:

C:

Sex: 43% M

Describe intervention (treatment/procedure/test):

-

Describe control (treatment/procedure/test):

-

Length of follow-up: minimum 12 months

Loss-to-follow-up:

-

Incomplete outcome data:

-

Outcome measures and effect size (include 95%CI and p-value if available):

Histories and developmental assessments of the 30 infants indicated developmental delay in 22 infants (73%), seizures in 17 infants (57%), cerebral palsy in 10 infants (33%), and prematurity in 9 infants (30%). Five infants had hearing deficits (17%), and 2 infants had microcephaly (7%).

Perinatal association: hydrocephalus in 9 infants (30%). Other associations included hypoxia or postnatal asphyxia in 8 infants (27%), and intracranial haemorrhage in 7 infants (23%). Meningitis was a postnatal association in five infants.

28 (93%) of the infants studied had normal pupillary responses. Nine infants (30%) had nystagmus other than optokinetic, including horizontal , pendular, downbeat, and searching nystagmus. Exaggerated widening of the palpebral fissure on reduction of ambient illumination was present in 12 of the 20 infants (60%) in whom it was tested. Each patient was tested for strabismus; exotropia was identified in 15 infants and esotropia in three (10%) infants. Most patients had mild hyperopia, as expected at this age. Astigmatism of greater than 2 dioptres , was the next most common refractive error, present in at least one eye in three of the 29 patients tested.

Neuroimaging:

An abnormality in the visual pathway was detected by computed tomography or MRI in 17 of 25 infants (68%).

Object vision developed in 15 of 300 patients during a follow-up period of 12 to 95 months.

Cortical visual impairment was diagnosed if the infant had poor vision at initial examination, absent optokinetic nystagmus, normal pupillary reflexes, and normal ocular structure

Geldof, 2015

Type of study: comparative, cross-sectional study

Setting: university hospital

Country: The Netherlands

Source of funding: a grant from the Novum Foundation, Huizen,

The Netherlands, a non-profit organization providing financial support

to (research) projects that improve the quality of life of individuals with

visual impairment (www.stichtingnovum.org).

Inclusion criteria: All VP/VLBW children originally participated in a multicenter randomized controlled trial comparing a home-based intervention and care as usual. At 5.5 y corrected age 160 of 176 children participating in the trial were available for follow-up, of whom 136 (77%) agreed to participate and 105 successfully completed the assessments

Exclusion criteria: severe congenital abnormalities, severe maternal physical or mental conditions, not mastering the Dutch language and unavailability of an interpreter, and participation in other trials on postdischarge management

N total at baseline:

Intervention: 105

Control: 67

Important prognostic factors²:

Gestational age ± SD:

VP/VLBW without CVI: 30.4 weeks (2.3)

VP/VLBW with CVI: 29.3 weeks (2.0)

C: 39.9 weeks (1.4)

Sex:

VP/VLBW without CVI: 51%

VP/VLBW with CVI: 52% M

C: 56% M

Groups comparable at baseline? Yes

Describe intervention (treatment/procedure/test):

very preterm birth (<32 wk of gestation) /very low birth weight (birth weight <1,500 g; VP/VLBW) children

Describe control (treatment/procedure/test):

Control children born at term

controls were recruited from regular schools attended by the VP/VLBW children (n = 29) and additional schools located in the same geographical area (n = 38). Controls were included if they had a GA >37 wk and BW >2,500 g. Exclusion criteria were parent reported severe perinatal complications or illnesses that might interfere with normal brain development, and learning difficulties.

Length of follow-up:

-

Outcome measures and effect size (include 95%CI and p-value if available):

25 (24%) of the VP/VLBW children met criteria for CVI, compared to 5 (7%) of controls (P = 0.006, OR: 3.86, 95% CI: 1.40–10.70).

Term children with CVI were excluded from further analysis.

VP/VLBW children with CVI had lower performance IQ, but not verbal IQ, than those without CVI. Visual problems in daily life were confirmed in VP/VLBW children classified with CVI. Additionally, difficulties in ospitalc and social

functioning were most prominent among VP/VLBW children with CVI.

CVI was defined after comprehensive oculomotor, visual sensory and perceptive assessment, and validated against vision problems in daily life and in terms of intellectual, ospitalc, emotional and social functioning, as well as use of therapeutic services.

Houliston, 1999

Type of study: cohort study

Setting: hospital

Country: Scotland

Source of funding: unknown

Inclusion criteria: patients who have hydrocephalus and who satisfied the following criteria was selected: binocular visual acuity at least 6/60, 5 years of age or older, previous treatment with a ventricular shunting procedure, recent high-quality CT scans, and intellectual and physical ability allowing cooperation with clinical assessment.

Exclusion criteria: neurological or ocular disorders

N total at baseline: 52

Important prognostic factors²:

age: 5-12 years

Sex: 56%M

Describe intervention (treatment/procedure/test):we identified the principal visual problems previously seen in our series of 20 children with disorders of cognitive vision (Dutton et al. 1996). From this a standardized clinical history-taking strategy was devised and administered to a group of 52 children with hydrocephalus in a similar age range as the control group.

Describe control (treatment/procedure/test):

we identified the principal visual problems previously seen in our series of 20 children with disorders of cognitive vision (Dutton et al. 1996). From this a standardized clinical history-taking strategy was devised and administered to 200 children without disorders of cognitive vision, aged between 5 and 12 years.

Length of follow-up:

Loss-to-follow-up:

Intervention:

N (%)

Reasons (describe)

Control:

N (%)

Reasons (describe)

Incomplete outcome data:

Intervention:

N (%)

Reasons (describe)

Control:

N (%)

Reasons (describe)

Outcome measures and effect size (include 95%CI and p-value if available):

Evidence of cognitive visual problems was identified in 27 of these children of whom 16 manifested multiple difficulties. The disabilities identified by our study comprised problems with: shape recognition, simultaneous perception, perception of movement, colour perception, orientation, object recognition, and face recognition

Patients with hydrocephalus

Deels ook UV2: ontwikkeling vragenlijst!

Huo, 1999

Type of study:

Setting: university hospital

Country: USA

Source of funding: Supported by National Eye Institute EY00384–01 (WVG) and by the Pacific Vision Foundation.

Inclusion criteria: We reviewed the records of approximately 7200 patients who were seen from 1979 to 1994 in a large paediatric ophthalmology referral Practice. Evaluation of these files revealed 170 cases of CVI.

Exclusion criteria: all children where poor visual function could be entirely attributed to non-cortical deficits

N total at baseline:

Intervention:

Control:

Important prognostic factors²:

For example

age ± SD:

I:

C:

Sex:

I: % M

C: % M

Groups comparable at baseline?

Describe intervention (treatment/procedure/test):

Describe control (treatment/procedure/test):

Length of follow-up:

Average length of follow-up was 5.9 years (range 3 months to 15 years)

Loss-to-follow-up:

10%

Reasons (describe): 56.5% returned for further evaluation

Incomplete outcome data:

Intervention:

N (%)

Reasons (describe)

Control:

N (%)

Reasons (describe)

Outcome measures and effect size (include 95%CI and p-value if available):

170 patients with CVI were 2.4% of all patients seen

The average patient

age was 3 years. Initially, the average level of

vision was 2.1 as measured by our scale. Thirty

eight patients (22.4%) had homonymous hemianopsia

in addition to CVI.

Aetiologies associated with CVI patients:

Perinatal hypoxia 38 (22.4%)

CVA 24 (14.1%)

Meningitis/encephalitis 21 (12.4%)

Acquired hypoxia 17 (10.0%)

Hydrocephalus 16 (9.4%)

Idiopathic 16 (9.4%)

Premature (<34 weeks’ gestation) 13 (7.7%)

Intracranial cyst 9 (5.3%)

Head trauma 7 (4.1%)

Seizures 7 (4.1%)

Congenital microcephaly 5 (2.9%)

Brain tumour 4 (2.4%)

In utero drug exposure 3 (1.8%)

Other 11 (6.5%)

In 9.4% of cases we could not determine an aetiology for CVI.

Neuro- and ophtalmological deficits:

Ophthalmological deficits

alone 32 (18.8%)

Neurological deficits alone 51 (30.0%)

Both neuro- and ophthalmological deficits 79(46.5%).

No associated neuro- or ophthalmological deficits 8 (4.7%)

Most common neurological deficit was seizures, with a rate of 52.9%.

Other neurological deficits:

Cerebral palsy 25.9%, Microcephaly 15.3% Hemiparesis 11.8% Hypotonia 5.3%

diagnosis of “CVI” was based upon (1) vision loss in the absence of signs of anterior visual pathway disease, or (2) vision loss greatly exceeding that which would be expected, given the findings of an ocular examination.

Khetpal, 2007

Type of study: chart review

Setting: teriary care referral facility

Country: USA

Source of funding: unknown

Inclusion criteria:

Records of patients evaluated at the Vanderbilt Eye Institute during the period of 2002 to 2005 with a diagnosis of CVI (International Classification of Disease (9^th ed.) 377.75) were identified via a search of billing records blindness” but is used for CVI at this institution and for all causes of childhood vision acuity loss not due to ocular, refractive, or anterior afferent visual pathway disease.

Exclusion criteria:

N total at baseline:

Intervention:

Control:

Important prognostic factors²:

For example

age ± SD:

I:

C:

Sex:

I: % M

C: % M

Groups comparable at baseline?

Describe intervention (treatment/procedure/test):

Clinical picture

Ophtamologic evaluation

Neurologic evaluation

Ocular evaluation:

Visual acuity:

Neuroimaging with MRI or CT

Describe control (treatment/procedure/test):

-

Length of follow-up:

Follow-up data were available for 52 patients (range, <1 year: 10; 1-1.9 years: 15; 2-4 years: 21; >4 years: 6). The visual function at final follow-up was compared with initial examination.

Loss-to-follow-up: 63

Reasons: these patients were primarily lost because their charts had been purged, it is possible that they had either substantial improvement in acuity or remained blind

Incomplete outcome data:

Outcome measures and effect size (include 95%CI and p-value if available):

Etiology:

perinatal hypoxia (35%), prematurity (29%), hydrocephalus (19%), structural central nervous system abnormalities (11%), and seizures (10%).

Many children (69%) had multiple aetiologies.

Ophtalmologic abnormalities:

esotropia (19%), exotropia (40%), nystagmus (21%), and optic atrophy (42%).

Neurological deficits:

Associated neurological findings included seizures (60%), cerebral palsy (37%), periventricular leukomalacia (12%), hemiparesis (21%), and hearing loss (11%).

Ocular abnormalities:

Strabismus was common and was typically exotropic. Optic atrophy occurred in over 40% of the patients but was usually mild. Seven of the children had known hypoxic episodes or hypoxic ischemic changes in the cortex on neuroimaging. Nystagmus was observed in 21.4% of the patients.

Significant refractive error (>+3.00 D or <-2.00 D) was common (20%).

Visual acuity:

Visual acuity tended to improve slightly over

time, although 40% had no improvement

MRI or CT:

About 70% of the patients received either a CT or a MRI at the time of diagnosis of CVI. As expected, the majority of these imaging results (83%) were abnormal

The diagnosis of CVI was based on an ocular examination that revealed poor visual function bilaterally that could not be accounted for by age, structural ocular examination findings, optic atrophy, or high refractive error. When patients had coexistent optic atrophy and CVI, a clinical decision during the examination was made based on the primary reason for the visual loss. The decision-making was based on the pupillary reactivity, the disk appearance, and the history of the structural central nervous system lesions.

Mac-Intyre-Beon, 2013

Type of study: prospective, controlled investigation of a cohort of prematurely born children

Setting: university hospital

Country: UK

Source of funding: This study was funded by the Chief Scientist’s Office, Scottish Government Health Directorates ref CZG/2/370

Inclusion criteria:

46 (17 females) of 71 invited able bodied primary school children born between prematurely, who agreed to attend following invitation. They were identified by a consultant paediatrician from a routine follow-up clinic for prematurely born children at the neonatal unit of the Queen Mother’s Maternity Hospital, Glasgow, on the basis that they had shown no evidence of neurodisability, nor required therapy.

Exclusion criteria: All control children met the entry criteria of having no special needs or reading difficulties and having been born at term (>=37-week gestation), and all attended mainstream schools in the same area as the study group

N total at baseline:

Intervention: 46

Control: 130

Important prognostic factors²:

age range:

I: 5.5–12.3 years

C: 4.7–11.7 years

Sex:

I: 63% M

C: % M

Describe intervention (treatment/procedure/test):

mainstream primary school

children, born between 1996 and 2000, prematurely born with gestations of 24.0–34.6 weeks (median 31.3)

(N=46)

Describe control (treatment/procedure/test):

control (term-born) school children

(N=130)

Length of follow-up:

Loss-to-follow-up:

Intervention:

N (%)

Reasons (describe)

Control:

N (%)

Reasons (describe)

Incomplete outcome data:

Intervention:

N (%)

Reasons (describe)

Control:

N (%)

Reasons (describe)

Outcome measures and effect size (include 95%CI and p-value if available):

visual perception assessment For all four visual perception tests (visual closure, global form, global motion, face processing) , prematurely born children had poorer scores than controls

15 (33%)of the prematurely born children had visual difficulties, where the remaining 31 prematurely born children had few if any difficulties.

The children with visual difficulties also had lower birth weight, shorter gestation, poorer Apgar scores and a greater proportions of males and emergency section deliveries, although these differences were not statistically significant.

ospitalc functions:

The prematurely born children with visual difficulties had abnormalities of contrast sensitivity, and eye alignment and stereoacuity, but such differences were not identified for measured visual fields or visual acuity.

Visual attention:

For all four tests, prematurely born children had significantly poorer scores than controls.

Clinical picture:

grouped visual difficulties experienced by the affected children alongside the presence or absence of problems by subsection of the inventory.

The feature common to all the cases is difficulty handling complex visual scenes. This manifested, for example, as difficulty finding someone in a group.

Ortibus, 2009

Type of study:

Setting: university hospital

Country: Belgium

Source of funding: unknown

Inclusion criteria: Records from the patients visiting our CVI clinic from January 2001 up to July 2006 were reviewed. Children with suspected visual

perceptual problems were referred.

Exclusion criteria: incomplete test battery

N total at baseline: 70

Important prognostic factors²:

Mean age ± SD: 7.0 ± 3

Sex:

I: % M

C: % M

Groups comparable at baseline?

Describe intervention (treatment/procedure/test):

L94 test battery consisting of five tests

The L94 is a compilation of eight visual perceptual tasks, specifically designed by our group to test visual perceptual difficulties in children. In five computer tasks (visual matching, overlapping line drawings, line drawings occluded by noise, De Vos task, unconventional object views), the child is required to identify everyday objects. The remaining three tasks require pen and paperwork and manual coordination, and are thus not always applicable for children with a central motor disorder. Testing was performed by a trained neuropsychologist

(PS).

Describe control (treatment/procedure/test):

Length of follow-up:

-

Outcome measures and effect size (include 95%CI and p-value if available):

One-third of the patients eventually received a diagnosis of visual perceptual deficit.

In the group with CVI, about half of the patients had a history of preterm birth.

Evaluation of the test battery:

In the first part of the study, an analysis of the test results on the five computer tasks was performed (Fig. 2). For this, a ranking was given to each category on the test as follows: <Pc 5=1 (worst result); Pc 5 to 10=2; Pc 10 to 25=3; Pc 25 to 50=4; Pc 50 to 75=5; >Pc 75=6 (best result).

Comparison of the different subtasks when looking at their distribution above or under Pc 50, showed that VISM is the only subtask scored >Pc 50 in most of the patients (n=55 or 78%). OVERL, NOISE, DE VOS, and VIEW are nearly equally distributed.

Subtask profiles showed considerable variability. VIEW was situated in the £Pc 5 category in 24%. The observed variability in subtask profiles indicates that the subtask can measure different visual perceptual abilities. Moreover, comparison of each subtask to the other ones, does not show any correlations

UV2?

Ozturk, 2016

Type of study: cross-sectional, retrospective chart review

Setting: paediatric ophthalmology and strabismus unit; a tertiary referral clinic and part of a multispecialty university hospital

Country: Turkey

Source of funding: unknown

Inclusion criteria: patients seen between June 2002 and May 2014 in the unit; Cases with a significant visual impairment, which was defined as BCVA less than 0.3 in their better eye using the Snellen chart in accordance with WHO criteria, were included in the present study. Cases who had no central fixation and who had signs of very poor vision, like searching nystagmus, ocular bobbing or oculodigital massage, were also included.

Exclusion criteria: -

N total at baseline: 695

Important prognostic factors²:

Mean age ± SD: 47.0 ± 51.9 months

Sex:

58 % M

Describe intervention (treatment/procedure/test)

-

Describe control (treatment/procedure/test):-

Length of follow-up:

-

Outcome measures and effect size (include 95%CI and p-value if available):

CVI was present in 212 cases (30.5%) and 20.3% of those who had a history of premature birth. Asphyxia, metabolic disorders, genetic syndromes, infections and trauma were identified as other risk factors for CVI in our population.

The time of insult was unknown in 278 patients (40.0%), of whom 61.5% had CVI, including hypoxic ischaemic encephalopathy (HIE), cerebral palsy, neurometabolic disorders and hydrocephalus. Chorioretinal dysplasia (21.6%) and primary optic atrophy (9.0%) were the other common pathologies in such cases.

Bilateral decreased visual response caused by damage to either the visual cortex or the geniculostriate visual pathways based on MRI findings was defined as cortical visual impairment (CVI), unless any ocular abnormalities related to visual loss existed.

Shah, 2006

Type of study: retrospective cohort study

Setting: university ospital

Country: Canada

Source of funding: unknown

Inclusion criteria: Infants who had an acute perinatal event were eligible if they met the following 3 criteria: (1) Apgar score of less than 5 at 5 minutes, metabolic acidosis (base deficit >16 mmol/L) in cord arterial blood or the first postnatal blood gas sample within 4 hours of birth, or delayed onset of breathing for more than 5 minutes; (2) need for mechanical ventilation immediately after birth and (3) moderate to severe encephalopathy including altered state of consciousness and/or seizures.

Exclusion criteria: encephalopathies associated with preterm birth, congenital abnormalities including subtle dysmorphism of unknown significance, a major single-organ anomaly, inborn errors of metabolism, congenital viral infection, septic shock, or cranial birth trauma, patients with evidence of antenatal events causing prenatal injury such as prolonged loss of fetal movements, arthrogryposis, or lack of fetal heart rate variability on admission of the mother to the hospital, and patients with severe meconium aspiration syndrome with persistent and prolonged postnatal hypoxemia

N total at baseline: 345 (302 with complete data)

Important prognostic factors²:

Mean age: 30 months (18-36 months)

Sex:

 59% M

Describe intervention (treatment/procedure/test):

logistic regression model of only 3 predictors with high statistical significance (administration of chest compressions >1 minute, onset of breathing >30 minutes, and base deficit value >16 in any blood gas analysis within the first 4 hours from birth)

Describe control (treatment/procedure/test):-

Length of follow-up:

24 months

Incomplete follow-up:

115 died (median age at death was 48 hours)

Incomplete outcome data:

43

The missing data were type of asphyxia (n=30), blood gas analysis results (n=19), and time of onset of respiration (n=1) (some children had missing data for >1 variable).

Comparisons of the predictive variables indicate that the 73 children lacking data (30 children who were missing outcome data and 43 who were missing predictor variable data) had less severe neonatal illness than the 302 children with complete data

Outcome measures and effect size (include 95%CI and p-value if available):

115 died, 111 had severe adverse outcome and 119 did not have this outcome

severe adverse outcome, was defined as death or severe disability (severe cerebral palsy, severe developmental delay, sensorineural deafness, or cortical blindness singly or in combination).

Six independent predictors of outcomes were identified. Using the 3 most significant predictors (chest compressions, age at onset of respiration, and base deficit), severe adverse outcome rates were 46% (95% confidence interval, 33%-58%) with none of the 3 predictors, 64% (95% confidence interval, 54%-73%) with any 1 predictor, 76% (95% confidence interval, 66%-85%) with any 2 predictors, and 93% (95% confidence interval, 81%-99%) with all of the 3 predictors present.

Outcome prediction rule

Included cortical blindness, but data are not separately presented for cortical blindness

Van Genderen, 2012

Type of study: cross-sectional study

Setting: tertiary care

Country: The Netherlands

Source of funding: unknown

Inclusion criteria: children with good binocular visual acuity, mean age 8 year, referred to the institute with a suspicion of CVI and subsequently diagnosed as having CVI following a detailed visual assessment, full ophthalmologic assessment and orthoptic examination; also they were assessed by an experienced child psychologist with a (neuro)psychological) test battery

Exclusion criteria: other diagnosis

N total at baseline: I=30

C=23

Important prognostic factors²:

Mean age: 8 years

Sex:

I: % M

C: % M

Groups comparable at baseline?

Describe intervention (treatment/procedure/test):

Children with CVI

Describe control (treatment/procedure/test):

Children without CVI

Length of follow-up:

-

Outcome measures and effect size (include 95%CI and p-value if available):

Children with CVI:

21 were born prematurely before 35 weeks of gestation, 7 suffered perinatal asphyxia, and 2 had a developmental brain abnormality. 20 children had mild to moderate cerebral palsy, 8 children had epilepsy.

86% of the children had MRI abnormalities; prematurely born children mainly had periventricular leukomalacia, while perinatal hypoxic-ischemic events in term-born children mostly resulted in cerebral infarction. MRI findings were considered normal in 4 children, in 2 children no MRI’s were made.

All children had a single optotype acuity of more than 20/40 (less than 0.3logMAR), 6 children had a visual acuity of 20/20 (0.0logMAR); 41% (12/29) had a crowding ratio >=2.0. Visual field defects were found in 53% (16/30) of children. Ophtalmologic examination showed partial optic atrophy in 5 children and significant refractive error in 3 (2 hyperopia, 1 myopia); 10 children had nystagmus. The CVI questionnaire showed 3 or more affirmative answers in all children; dorsal stream problems were reported more frequently than ventral problems.

In children without CVI only 23% had an abnormal clinical history. Only 1 MRI out of 6 was abnormal.

Wong, 1991

Type of study: cohort study

Setting: university hospital

Country: Hong Kong

Source of funding: unkown

Inclusion criteria: patients with severe visual loss in the presence of normal pupillary response and normal fundi, admitted between 1985 and 1990

Exclusion criteria: when the duration of visual loss lasted less than 48 hours

N total at baseline: 34

Important prognostic factors²:

age ± SD: 1 month to 14 years

Sex: 59% M

Describe intervention (treatment/procedure/test):

Multidisciplinary evaluation

Flash VEP

EEG

Photic stimulation

Cranial CT

Describe control (treatment/procedure/test):-

Length of follow-up: 1-5 years

Loss-to-follow-up:

-

Incomplete outcome data:

-

Outcome measures and effect size (include 95%CI and p-value if available):

Congential Cortical Blindness: 7

Lissencephaly 3

Mitochondrial myopathy 1

Cerebral palsy 4

Abnormal VEP: 6

Abnormal EEG: 7

Acquired cortical blindness: 27

Hypoxia: 14

Severe perinatal asphyxia: 1

Cardiac arrest: 2

Severe hypotensive episodes following cardiac surgery: 5

Status epilepticus: 6

Encephalitis or meningitis: 6

Hydrocephalus with shunt malfunction: 1

Hydrocephalus with subdural hematoma, cerebral thrombosis, intracranial haemorrhage, and head trauma in 1 each

Unclear: 3

Cerebral palsy: 19

Mental retardation: 22

Myoclonic epilepsy: 7

Generalized tonic-clonic epilepsy: 6

Complex partial seizure: 1

Deafness: 1

VEP: 6/23 normal

EEG: 5/24 normal

Cranial CT: 11/27 cerebral atrophy

Bioccipital infarction: 1

Study reference

Study characteristics

Patient characteristics

Index test

(test of interest)

Reference test

Follow-up

Outcome measures and effect size

Comments

García-Ormaechea, 2014

Type of study: Validation study

Setting: clinic

Country: Spain

Conflicts of interest: None of the authors has any conflict of interest

Inclusion criteria: infants younger than 24 months of age who visited the clinic for any concern (i.e., strabismus, retinopathy of prematurity, refractive error, …) were included in the study, until all age groups reached the minimum number of children.

Exclusion criteria:

N=220

Normal visual maturation (NVM): 128

Abnormal visual maturation (AVM): 92

Mean age (months) ± SD:

NVM: 10.6 ± 6.8)

AVM: 11.2 ± 7.2

Sex:

NVM: 53.5% M

56.5% M

Describe index test: Preverbal Visual assessment (PreVias) Questionnaire that assesses visual cognitive integrative functions in 30 questions that assesses four cognitive domains:

Visual attention

Visual communication

Visual-motor coordination

Visual processing

Cut-off point(s):

This examination classifies visual domain scores as appropriate or not appropriate for the infant's age. Infants with at least one domain scored as not appropriate for their age were diagnosed with abnormal visual maturation (AVM) Questionnaire domain scores were compared with the results of clinical behavioural assessments for the same four domains using ranked comparisons (Kendall's coefficient of concordance, tau). We selected cut-off points with the best balance between sensitivity and specificity for every age group. Sensitivity, specificity, and positive and negative predictive values were calculated globally and for every age group in each domain.

Describe reference test:

Clinical behavioural assessments for the same four domains

Visual acuity was assessed using LEA grating paddles and scored from 0 to 16 cycles per degree. The visual assessment included ocular motility, cycloplegic refraction, fundoscopy, and visual behavioural assessment. Because no standard behavioural protocol exists for the visual assessment of infants (b24 months of age), we designed a test battery based on the VAP–CAP assessment. It is a visual assessment procedure (VAP)which evaluates capacity, attention and processing (CAP) of infants. It was designed to evaluate children with visual impairments. Our clinical battery consists of 51 items that sample the same four cognitive visual abilities measured by the questionnaire: visual attention, visual communication, visual–motor coordination, and visual processing. This examination classifies visual domain scores as appropriate or not appropriate for the infant's age.

Time between the index test and reference test: father, mother, or other primary caregiver of the infant completed the questionnaire at the beginning of the clinical visit, before the clinical evaluation

In 25% of the cases, the questionnaire was administered again within 7 days for the test–retest analysis.

For how many participants were no complete outcome data available? -

N (%)

Reasons for incomplete outcome data described? -

Outcome measures and effect size (include 95%CI and p-value if available):

Cut-off points were selected for each visual domain and each age group.

With the selected cut-off points, the specificity of the PreViAs questionnaire was:

visual attention 86.5%

visual communication 89.5%

visual–motor coordination 81.5%

visual processing 81.3%

sensitivity

visual attention 79.2%

visual communication 64.2%

visual–motor coordination 77.9%

visual processing 67.5%

More than 80% of the infants were correctly classified by the questionnaire (Negative predictive value).

visual attention 93.7%

visual communication 85.0%

visual–motor coordination 89.1%

visual processing 81.3%

Test accuracy (area under the receiver operating characteristic)

visual attention 0.829

visual communication 0.768

visual–motor coordination 0.797

visual processing 0.744

Test–retest reliability

visual attention 0.97,

visual communication 0.94,

visual–motor coordination 0.98

visual processing 0.98.

Focuses on abnormal visual maturation

geeft wel aanwijzingen welke kinderen verder onderzocht moeten worden omdat zij een afwijkende abnormale visuele ontwikkeling laten zien onder 24mnd.

MacIntyre- Beon, 2012

Type of study: Validation study

Setting: clinic

Country: Scotland

Source of funding: This study was partly funded by Medical Research

Scotland Grant Study Number: 106FRG

Inclusion criteria:

Patients (P): Consecutive children presenting to the clinic with problematic CVI, and controls consisting of children attending 7 mainstream primary schools

Exclusion criteria: poor reading skills, dyspaxia, autism and other behavioural disorders

N

P: 36

C: 156

Mean age ± SD:

P: 10.8 ± 3.1

C: 8.2 ± 1.9

Sex: not reported

Other important characteristics: not reported

Describe index test: 51-question inventory, in seven sections

1 Visual fields

2 Perception of movement

3 Search

4 Guidance of movement

5 Attention

6 Crowded scenes

7 Recognition and navigation

Cut-off point(s):

Describe reference test:

-

Time between the index test and reference test: -

Intra-rater reliability was tested by 19 consecutive families completing the inventory twice, one week apart.

For how many participants were no complete outcome data available? -

N (%)

Reasons for incomplete outcome data described? -

Outcome measures and effect size (include 95%CI and p-value if available):

Internal reliability was tested with Cronbach’s α (comparing the variance in response for individual questions, to the

variance in response for the whole section).

Section controls patients

1 0.91 0.81

2 0.95 0.81

3 0.98 0.71

4 0.68 0.77

5 0.98 0.56

6 1.0 0.82

7 1.0 0.77

Intra-rater reliability was tested by 19 consecutive families completing the inventory twice, one week apart. The intra-class correlation was 0.98.

Validation study described in a letter to the editor, without a reference test

Ortibus, 2011

Type of study: validation study

Setting: tertiary care referral center

Country: Belgium

Conflicts of interest: not reported

Inclusion criteria: children referred because of a suspicion of CVI on the basis of behavioural features and/or clinical exam between August 2008 and August 2010

Exclusion criteria: -

N= 91

Gestational age ± SD: 37 (24-41)

Age at examination (months): 82 (41-204)

Sex: 64% M /36 % F

Other important characteristics:

Cerebral palsy: 45%

Autism spectrum disorders: 12%

Developmental dyspraxia: 3.3%

Describe index test: CVI questionnaire of 46 closed items on six domains: Evaluating Visual Attitude, Ventral and dorsal stream functions, Complex (visuomotor) abilities, Use of other Senses and associated CVI characteristics, Associated CVI characteristics

Cut-off point(s): 3, 4 or 5

Describe reference test: diagnostic evaluation at a face to face appointment: presence of cerebral palsy; gestational age, birth weight, and gender recorded. Also presence of neurodevelopmental diagnoses such as autism spectrum disorder, developmental coordination disorder, and presence of epilepsy

Neurophtamolgic evaluation including:

Qualitative observation

Visual field measurement

Visual acuity measurement

Quantitative assessment of presence of strabismus/nystagmus

Cognitive assessment

Visual perceptual assessment

Imaging characteristics

Cut-off point(s):

Time between the index test and reference test:

For how many participants were no complete outcome data available?

N (%)

Reasons for incomplete outcome data described? -

Outcome measures and effect size (include 95%CI and p-value if available):

Sum score based on 6 domains and clinical test score (L94) resulted in AUC of 0.69

CVI questionnaire

Philip, 2016

Type of study: Validation study

Setting: teriary care teaching hospital

Country: India

Conflicts of interest: None

Inclusion criteria: all children below 18 years of age, referred by paediatricans, paediatric neurologists and child psychiatrists to the CVI Clinic from March 2011 to February 2012

Exclusion criteria:

N= 342

Prevalence:

Mean age ± SD: 3.8 (Range 0-17)

Sex: 35.7% M / 64.3% F

Other important characteristics:

Describe index test: Structured Clinical Question Inventory (SCQI)

Cut-off point(s):

Comparator test:

Cut-off point(s):

Describe reference test:

none

Cut-off point(s):

Time between the index test en reference test:

For how many participants were no complete outcome data available?

N (%)

Reasons for incomplete outcome data described?

Outcome measures and effect size (include 95%CI and p-value if available):

Face validity:

rank ordering, without any reservation, of all the items of SCQI as measuring the clinical entity of CVI suggested that the measure has good face validity

content validity:

practicing ophthalmologists considered that all the dimensions of CVI were represented by the existing items in the SCQI and did not include any other item when they were given the choice, suggesting a good content validity

construct validity:

internal consistency of the SCQI: Cronbach’s α) of the SCQI as a whole was 0.93 and for each domain it ranged from 0.92 to 0.94. The total domain correlation ranged from 0.02 for the domain of Neglect to 0.74 for the Foreground clutter

India

Further empirical testing needed before using in other cultures

No reference test, only face validity and content validity described

Wel meenemen: maar beperking aangeven dat deze nog gevalideerd moet worden tegen een externe referentiestandaard

Salavati, 2017

Type of study: Face validity study

Setting: tertiary care centre for blind and partially sighted people

Country: the Netherlands

Funding: Novum Foundation (OIO323), a Dutch non-profit organisation providing financial support to (research) projects that improve quality of life of individuals with visual impairments

Inclusion criteria: Children with any type of CP with and without CVI were recruited from Royal Dutch Visio and allied healthcare practices. Inclusion criteria were presence of CP and CVI, mild or moderate intellectual disability, and age at testing of the CVI-MQ for children between 4 and 16 years.

Exclusion criteria: hearing difficulties (>30 dB hearing loss) and severe or profound intellectual disability (IQ<40)

N=82

CP:

CVI:

Mean age ± SD:

CP: 11.5 ± 4

CVI: 10 ± 3.5

Sex: % M / % F

Other important characteristics:

Describe index test: CVI motor questionnaire

The content of the CVI-MQ for children with GMFCS levels I, II and III includes motor items for children about higher motor skills such as walking, stairclimbing and jumping, while the CVI-MQ for children with GMFCS levels IV and V contains motor skills such as rolling over and reaching.

For more details see publication

Cut-off point(s):

Comparator test:

Cut-off point(s):

Describe reference test:

Cut-off point(s):

Time between the index test en reference test:

For how many participants were no complete outcome data available?

N (%)

Reasons for incomplete outcome data described?

Outcome measures and effect size (include 95%CI and p-value if available):

The results of the ROC curve for CVI-MQ, GMFCS levels I, II and III are sensitivity 1.00 and specificity 0.96

CVI-MQ, GMFCS levels IV and V sensitivity 0.97 and specificity 0.98.

we developed two CVI-Motor Questionnaires for children with CP: one for GMFCS levels I, II and III and one for GMFCS levels IV and V.

These questionnaires measure the degree of presence or absence of CVI in children with CP

The MQs were completed by paediatric physical therapists and occupational therapists who were familiar with the child

Gaat over de motorische vaardigheden van kinderen met CVI

Doelstelling van dit onderzoek beschrijven

Zij gebruiken een scorings lijst vd motorische vaardigheden om de aan/afwezigheid van CVI aan te tonen. Wij moeten hem dus meenemen.

Study reference

Patient selection

Index test

Reference standard

Flow and timing

Comments with respect to applicability

García-Ormaechea, 2014)

Was a consecutive or random sample of patients enrolled?

Unclear

Was a case-control design avoided?

Unclear

Did the study avoid inappropriate exclusions?

Unclear

Were the index test results interpreted without knowledge of the results of the reference standard?

Yes

If a threshold was used, was it pre-specified?

No

Is the reference standard likely to correctly classify the target condition?

Yes

Were the reference standard results interpreted without knowledge of the results of the index test?

Yes

Was there an appropriate interval between index test(s) and reference standard?

Yes (same day)

Did all patients receive a reference standard?

Yes

Did patients receive the same reference standard?

Yes

Were all patients included in the analysis?

Yes

Are there concerns that the included patients do not match the review question?

Yes (abnormal visual maturation is not CVI)

Are there concerns that the index test, its conduct, or interpretation differ from the review question?

Yes (abnormal visual maturation is not CVI)

Are there concerns that the target condition as defined by the reference standard does not match the review question?

Yes (abnormal visual maturation is not CVI)

CONCLUSION:

Could the selection of patients have introduced bias?

RISK: UNCLEAR: normal patients younger than abnormal patients

CONCLUSION:

Could the conduct or interpretation of the index test have introduced bias?

RISK: LOW

CONCLUSION:

Could the reference standard, its conduct, or its interpretation have introduced bias?

RISK: LOW

CONCLUSION

Could the patient flow have introduced bias?

RISK: LOW

Ortibus, 2011

Was a consecutive or random sample of patients enrolled?

Yes

Was a case-control design avoided?

Yes

Did the study avoid inappropriate exclusions?

No

Were the index test results interpreted without knowledge of the results of the reference standard?

Unknown

If a threshold was used, was it pre-specified?

Unclear

Is the reference standard likely to correctly classify the target condition?

Yesr

Were the reference standard results interpreted without knowledge of the results of the index test?

Unclear

Was there an appropriate interval between index test(s) and reference standard?

Yes

Did all patients receive a reference standard?

Yes

Did patients receive the same reference standard?

Yes

Were all patients included in the analysis?

Yesr

Are there concerns that the included patients do not match the review question?

No

Are there concerns that the index test, its conduct, or interpretation differ from the review question?

No

Are there concerns that the target condition as defined by the reference standard does not match the review question?

No

CONCLUSION:

Could the selection of patients have introduced bias?

RISK: LOW

CONCLUSION:

Could the conduct or interpretation of the index test have introduced bias?

RISK: LOW

CONCLUSION:

Could the reference standard, its conduct, or its interpretation have introduced bias?

RISK: LOW

CONCLUSION

Could the patient flow have introduced bias?

RISK: LOW /HIGH/UNCLEAR