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Trial registered on ANZCTR

Registration number

ACTRN12618001111268

Ethics application status

Approved

Date submitted

23/06/2018

Date registered

4/07/2018

Date last updated

4/07/2018

Type of registration

Retrospectively registered

Titles & IDs

Public title

The prevalence of visual defects during early stages of stroke

Scientific title

The Epidemiology of Vision and Visual Field Defects after Acute stroke

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1212-6810

Trial acronym

VFAST

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Acute Ischemic Stroke

Visual field defects

Visual-Motor Capacity

Visual Field Integrity

Condition category

Condition code

Stroke

Ischaemic

Neurological

Neurodegenerative diseases

Eye

Diseases / disorders of the eye

Intervention/exposure

Study type

Observational

Patient registry

True

Target follow-up duration

Target follow-up type

Months

Description of intervention(s) / exposure

Vision and the visual processes occupy a large volume of brain yet stroke is diagnosed by its affects on motor processing. This is partly because to quantify the effects of stroke on visual capacity other than by screening tests, such as confrontation, is not easy especially in the early stages after acute stroke onset. At these stages patients are often debilitated or bedridden and can not undertake the complex, specialised testing needed for such evaluation.

We hope to address this limitation and better define the characteristics of acute stroke on vision and visual processing by using modern applications shown on portable tablet devices.

Our observational study was performed on one hundred and ten, consecutive patients admitted between June,2017-May,2018 to the Neurology Ward at Sunshine Hospital, Melbourne, and who were diagnosed as having suffered a stroke by conventional clinical diagnostic methods. All patients were bed-bound and were requested within 1 week after admission to volunteer for vision testing using two iPad applications “Melbourne Rapid Field” (MRF) App (visual acuity (threshold spatial vision), threshold visual field) and the "UNSW L-R Eye-Hand Coordination"App (visuo-motor capacity). Testing was performed at the bedside of stroke patients who volunteered to participate in this study consistent with our ethics clearance. Their visual acuity, visual field extent and visuo-motor skills were followed up at 3, 6 and 12 months to monitor recovery. The health care of all patients is being administered based on standard clinical practice and the vision testing outcomes will not impact on this management.

Intervention code [1]

Not applicable

Comparator / control treatment

Thirty age-similar controls were recruited as volunteers following an eye examination at a private optometry practice. They were tested using the same suite of vision tests (visual acuity, visual field and visual motor skills) in the optometry practice.

All recruitment complied with our HEC approval (HREC/16/WH/1). The control participants had no history of ocular, cognitive or neurological conditions that could be expected to impact on their vision and testing for visual fields or visual acuity.

Control group

Active

Outcomes

Primary outcome [1]

Visual Field Integrity using Mean Deviation (Mean of Threshold Deviation in dB) for the acute stroke group and its comparison to the control patients.

Instrument : Melbourne Rapid Fields (MRF) Application.
The Melbourne Rapid Fields-Neural app (MRF-neural) has been developed by GLANCE Optical Pty Ltd, Melbourne, Australia to measure thresholds across 21 degrees of the visual field using a large screen (12.9 inch) iPad Pro tablet (Apple, Cupertino, CA). The test is conducted at 33 cm with the patient wearing their habitual reading glasses. With central fixation, the 12.9-inch iPad screen subtends 22° x 17° (H x V) at the usual viewing distance of 33 cm (13 inches). The test pattern used by MRF-neural is a reduced and modified 24-2 Humphrey grid (clinical standard) that shows spots out to 21 degrees (instead of 27 degrees) with 4 extra spots added to central locations (0.8 degrees) to test foveal thresholds. Spot size has been scaled across the visual field to allow for the tangent effect of a planar screen and to produce constant spatial and probability summation which gives rise to a fixed threshold (30 dB) at all locations.

Patients respond to the presence of a spot by tapping the space bar on the keyboard connected to the tablet (NB the test can be performed without a keyboard). Thresholds are estimated using a Bayesian thresholding logic (Vingrys et al. Translational Vision Science & Technology (TVST), 2016). Reliability indices (false positive, negative and fixation loss) are polled during testing.

Voice commands can be generated by the tablet to instruct the patient on how to perform the test. These were used with our normal controls but at the bedside the voice over was turned off as we found operator input was faster and more flexible in performing the test with stroke patients. The design principles and procedural aspects of performing the visual field have been detailed elsewhere by Vingrys et al (TVST, 2016).

Timepoint [1]

Within one week after the onset of stroke for acute stroke.
Following a routine eye examination for controls

Primary outcome [2]

We will also measure the time taken undertaking a visuo-motor hand eye coordination task using UNSW L-R Hand-Eye Coordination App ( https:// newsroom.unsw.edu.au/news/science-tech/new-app-assess-eye-hand-coordination). Here the patient has to trace out 3 images on the ipad using an ipad pencil.

The time taken and number of errors created while tracing the images by stroke cases will be compared to the control group.This will provide a measure of the patient's fine motor skills during the acute stage of a stroke and determine whether these improve with time.

Timepoint [2]

Within one week after the onset of the stroke
Following a routine eye examination for controls

Primary outcome [3]

Visual Acuity will also be determined with and without luminance Noise using the MRF tablet application in patients with an Acute Stroke. Visual acuity to high contrast optotypes will be measured to ascertain whether patients meet the legal requirement for driving in Victoria following an episode of stroke.

Acuity will also be determined for optotypes immersed in noise as these are sensitive to abnormal brain processing such as occurs in amblyopia (Pelli et al. Journal of Vision. 2004) and might prove useful in cases of stroke where an elevated intrinsic level of noise is highly likely.

Timepoint [3]

Within one week since the onset of the stroke
Following a routine eye examination for controls

Secondary outcome [1]

The Visual Field Recovery
The longitudinal visual field recovery will be quantified using foveal threhsolds ,mean deviation of visual fields and quantified areas of visual field loss.

Timepoint [1]

3-months post initial assessment

Secondary outcome [2]

Fundus Photography

Given the common embryology of retinal neural and vascular beds with those of the cortex we will obtain fundus photographs of the retina for enface images to observe the retinal vascular status during the initial phase of an ischemic event in comparison to the visual fields and MRI/CT scans,

Timepoint [2]

3 months post-initial assessment

Secondary outcome [3]

Optical Coherence Tomography ( OCT)

Precise retinal cross-sectional data will be collected using optical coherence topography (resolution of 7-9 micron) from acute stroke patients. The changes in retina neural and vascular tissues will be compared with the quantified visual field changes and the brain MRI/CT scans during the patient's recovery period post stroke.

Timepoint [3]

6 months post-initial assessment

Eligibility

Key inclusion criteria

Any patient admitted with a clinical diagnosis of an ischemic acute stroke (within a week since the onset of the stroke) with no history of ocular, cognitive or neurological conditions that could be expected to impact on their visual acuity, visual fields or visuo-motor capacity.

All controls will have an age-similar profile to our stroke group and will have normal vision, eye health, brain health and systemic health. They will meet our exclusion criteria.

Minimum age

30 Years

Maximum age

No limit

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

Patients with:
1. medical record of co-existing ocular conditions such as glaucoma, macular degeneration, diabetes, cataracts or other causes of monocular vision loss (<6/9)
2. Severe cognitive or physical impairment that limits performance on tests
3. Inadequate English to understand the instructions for the testing
4. Poor reliably (errors >50%) on the visual fields
5. Acute stroke resultant to a heammorragic cause
Same exclusion criteria apply to the controls

Study design

Purpose

Natural history

Duration

Longitudinal

Selection

Defined population

Timing

Prospective

Statistical methods / analysis

Sample size has been calaculated from past studies which have recruited 50-100 participants for similar tasks. Moreover, given the variabiity reported for the MRF indices a sample size of 50 will be able to expose moderate to small effect sizes.

The Data will be analysed for:
1. The mean deviation from control of the patient's visual field
2. The foveal threshold
3. Visual Acuity to high contrast targets and those immersed in noise,
4. Visuo-motor capacity in the hand eye coordination task.

From previous studies we anticipate a large spread in our stroke group which will mean that parametric testing can not be applied. We will test for normality in the data and for homogeneity of variance and in its absence will adopt a Mann-Whitney U test for comparison of mid-points with an alpha of 0.05.

Data concordance will be established after raw scores had been converted into z-scores using a Person product moment correlation coefficient.

Diagnostic accuracy will be established using ROC analysis.

Recruitment

Recruitment status

Active, not recruiting

Date of first participant enrolment

Anticipated

Actual

2/07/2017

Date of last participant enrolment

Anticipated

Actual

4/05/2018

Date of last data collection

Anticipated

31/12/2019

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

VIC

Recruitment hospital [1]

Sunshine Hospital - St Albans

Recruitment postcode(s) [1]

3021 - St Albans

Funding & Sponsors

Funding source category [1]

Commercial sector/Industry

Name [1]

Glance Optical Pty Ltd

Address [1]

Level 1/430 Little Collins Street
Melbourne, Victoria 3000

Country [1]

Australia

Primary sponsor type

University

Name

The La Trobe University,Melbourne

Address

Room 122, Biological Sciences 2 Building.
La Trobe Univeristy,
Plenty Rd & Kingsbury Dr, Bundoora VIC 3086

Country

Australia

Secondary sponsor category [1]

Hospital

Name [1]

The Sunshine Hospital,Western Health,Melbourne

Address [1]

Western Health
Department of Neurology
176, Furlong Road
St Albans Vic 3021
Australia

Country [1]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Western Health Low Risk Human Research Ethics Panel

Ethics committee address [1]

Western Health Office for Research
Level 3 Western Centre for Health, Research & Education (CHRE)
Sunshine Hospital
Furlong Road
St Albans VIC 3021

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

06/09/2016

Approval date [1]

22/11/2016

Ethics approval number [1]

HREC/16/WH/1

Summary

Brief summary

Impaired motor function and cognitive confusion are the most common diagnostic symptoms associated with "stroke". Few acute clinical investigations of visual function are conducted even though far greater volumes of cortical and subcortical regions of the brain are directly involved with visual functions than with motor function. Van Essen et al (1984) first highlighted the vast number of visual areas and volume of cortex attributed to visual sensory processing, visual attention, visuo-motor functions and visually driven emotional processing. Furthermore the eye and the brain share similar embryonically derived vascular tissues and blood flow making vision defect a likely companion to a brain blood disorder (stroke).

Over the last decade Rowe et al (2009), Spotfforth et al (2017) and Quinn et al (2018) have described significant persistent visual deficits following stroke. Of those affected common visual deficits up to a year later include visual field loss (hemianopia, quadrantanopia) ,perceptual disorders (visual inattention/neglect) and eye movement disorders. Rowe et al (2009) also noted the large proportion of ocular alignment deficits co-morbid with visual field defects. Most recently Quinn et al (2018) highlighted the incidence of visual field deficits with coexisting visual neglect in post stroke survivors.

Hemifield neglect has long been known as a perceptual deficit sometimes associated with stroke although when tested it is most often tested manually by line bisection or star cancellation even though stroke itself is usually defined by motor impairments. Application of sophisticated visual field analyzers such as the Humphrey have seldom been utilized in hospitalized stroke patients given that most cases involve elderly patients limited in mobility and who suffer motor impairment for at least 24 hours.

Thus the purpose of this study was to consider whether visual field losses can be identified and quantified in the acute stages of stroke using an ipad based bed side perimetry app, The Melbourne Rapid Fields (MRF), developed to measure visual acuity and visual field integrity. The neuroanatomical site of lesion was also considered in relation to field deficits to evalute the clinical and radiographic imaging patterns with the patient’s visual acuity and visual field intergrity.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Prof Sheila Crewther

Address

La Trobe University
Room 122,Biological Sciences 2 Building,
College of Science, Health and Engineering,
Department of Psychology and Counselling
Plenty Rd & Kingsbury Drive,
Bundoora VIC 3086

Country

Australia

Phone

+61394792290

Fax

+61394791956

[email protected]

Contact person for public queries

Name

Prof Tissa Wijeratne

Address

Director,Department of Neurology and Stroke Services,
Level 3,WCHRE Building,
Sunshine Hospital,
176,Furlong Rd,St Albans ,
Vic 3021

Country

Australia

Phone

+61383456766

Fax

+61383456882

[email protected]

Contact person for scientific queries

Name

Prof Sheila Crewther

Address

La Trobe University
Room 122,Biological Sciences 2 Building,
College of Science, Health and Engineering,
Department of Psychology and Counselling
Plenty Rd & Kingsbury Drive,
Bundoora VIC 3086

Country

Australia

Phone

+61394792290

Fax

+61394791956

[email protected]

No information has been provided regarding IPD availability

What supporting documents are/will be available?

Current supporting documents:

Updated to:

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
23609	Ethical approval					374683-(Uploaded-15-06-2020-00-12-51)-Study-related document.docx
23610	Informed consent form			[email protected]		374683-(Uploaded-15-06-2020-01-31-49)-Study-related document.HEIC

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Acquired Visual Deficits Independent of Lesion Site in Acute Stroke.	2020	https://dx.doi.org/10.3389/fneur.2020.00705
Dimensions AI	Vision and Visuomotor Performance Following Acute Ischemic Stroke	2022	https://doi.org/10.3389/fneur.2022.757431

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically