Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12619000057189
Ethics application status
Approved
Date submitted
20/11/2018
Date registered
16/01/2019
Date last updated
3/11/2021
Date data sharing statement initially provided
16/01/2019
Date results provided
3/11/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Spectacle interventions for treating eye strain with computer use
Scientific title
Investigating spectacle interventions for computer vision syndrome by assessing the change in subjective visual fatigue score and critical flicker frequency pre and post computer task.
Secondary ID [1] 296385 0
None
Universal Trial Number (UTN)
U1111-1222-9240
Trial acronym
Linked study record
Nil

Health condition
Health condition(s) or problem(s) studied:
Computer vision syndrome 310135 0
Condition category
Condition code
Eye 308881 308881 0 0
Diseases / disorders of the eye

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Description of interventions (prior to publication of the study findings) - as per original registry entry details:

1. The subjects will be randomised to one of four spectacle lenses of different brands. Intervention 1 – spectacle lens brand 1; intervention 2 – spectacle lens brand 2; intervention 3 – spectacle lens brand 3; intervention 4 – spectacle lens brand 4.

2. For the purposes of the study, “laboratory conditions” denotes the running of the experiment within a designated research laboratory space, in which critical aspects of the tasks (e.g. equipment, light levels, absence of other distractions) are well-controlled environment, and run according to a standardized procedure.

3. Participants will be advised to wear spectacle lenses for a total duration of 2-hours whilst performing the computer task, which involves transcribing numbers from a PDF document into a spreadsheet and identifying data entry errors from a document presented on a computer screen.


Description of interventions (submitted as private notes in the original registration process, but now being entered into the public domain, further to publication of the study findings):

In this study, we sought to quantify the magnitude of how much practitioner advocacy can augment the response of patients to blue light filtering spectacle interventions, in patients who believe they have been administered the intervention.

Our study contains a placebo treatment (i.e. conventional non blue light filtering spectacle lenses not designed to alleviate CVS), but all patients will be led to believe they have received an active treatment. The nature of this deception is therefore not described in the publicly visible documentation for the study, to prevent this deception being unmasked. In both the treatment and placebo groups, half of participants will be instructed (using a standardized script) that there is strong clinical impression that the treatment is effective, whereas the other half will be instructed that there is a strong clinical impression that the treatment is not effective. Our study design therefore allows us to simultaneously measure treatment effects (i.e. overall difference between treatment and placebo arm) as well as how practitioner advocacy influences CVS outcomes in patients who believe they have received a treatment (i.e. overall difference between advocacy verses non-advocacy arms).
For the intervention group “Essilor Prevencia” blue light filtering lenses will be used, and for the control group non-blue light filtering spectacle lenses with a conventional anti reflection coating will be used.

So, the 4 intervention arms comprise:
1. Blue-light filtering lenses + positive clinician advocacy
2. Blue-light filtering lenses + negative clinician advocacy
3. Non blue-light filtering lenses (control) + positive clinician advocacy
4. Non blue-light filtering lenses (control) + negative clinician advocacy
Intervention code [1] 312721 0
Treatment: Devices
Comparator / control treatment
Description of interventions (prior to publication of the study findings) - as per original registry entry details:
“Intervention 4 – spectacle lens brand 4” will be the comparator.

Description of interventions (submitted as private notes in the original registration process, but now being entered into the public domain, further to publication of the study findings):
4. Non blue-light filtering lenses (control) + negative clinician advocacy
Control group
Dose comparison

Outcomes
Primary outcome [1] 307861 0
Patient symptoms – measured using a visual fatigue questionnaire survey score (developed by Sheedy et al., 2003 [Sheedy et al. Is all asthenopia the same? Optom Vis Sci. 2003 Nov;80(11):732-9]) designed to grade the severity of visual fatigue.
Timepoint [1] 307861 0
Change in visual fatigue score pre and post 2-hours of computer task
Primary outcome [2] 307862 0
Critical flicker frequency - measured using a custom-built light emitting diode-based stimulus
Timepoint [2] 307862 0
Change in critical flicker frequency measurement pre and post 2-hours of computer task.
Secondary outcome [1] 353166 0
Blink rate will be assessed by recording the eyes with a web-camera, so that the number of blinks can be counted off-line.
Timepoint [1] 353166 0
Change in total number of eye blinks per minute, at the beginning (5 minutes) and end (5 minutes) of the 2-hour computer task.
Secondary outcome [2] 353167 0
Eye movements – measured using a saccadometer (Ober Consulting, Poznan, Poland) instrument.
Timepoint [2] 353167 0
Change in eye movements, pre and post 2-hours of computer task.
Secondary outcome [3] 353168 0
Near point of convergence quantified using the push-up method.
Timepoint [3] 353168 0
Change in near point of convergence pre and post 2-hours of computer task.
Secondary outcome [4] 353337 0
Incidence of adverse events
1. The adverse events will be self-reported by the participants
2. The present study is designed to elicit a level of computer vision syndrome by making the participants perform computer task for 2-hours, following which the symptoms will be assessed using a 9-item questionnaire which captures degree of eye strain, blurred vision, ocular irritation, double vision, burning sensation, dry eyes, tearing of eyes, and headache. As such, these induced effects are not adverse affects. However, an adverse event which could result with prolonged computer use is muscular-skeletal discomfort.
Timepoint [4] 353337 0
At the end of the of the 2-hour computer task.
Secondary outcome [5] 365392 0
Near point of accommodation quantified using the push-up method.
Timepoint [5] 365392 0
Change in near point of accommodation pre and post 2-hours of computer task.

Eligibility
Key inclusion criteria
- Computer users with symptoms of computer vision syndrome (as determined by a standardised questionnaire, developed by Segui Mdel et al. 2015 [Segui Mdel et al. A reliable and valid questionnaire was developed to measure computer vision syndrome at the workplace. J Clin Epidemiol, 68(6), 662-673])
- Habitual use of computer without spectacles
- Unaided binocular near vision of greater than N8 at 30 – 40 cm
Minimum age
18 Years
Maximum age
40 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
- Neurological disease (by self-report)
- Migraine (by self-report)
- Nystagmus
- Optometrist/Ophthalmologist/Orthoptist/OD students and dispensing opticians


Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
After individuals provide consent, they will be randomised to one of four spectacle interventions. Allocation will be concealed using sealed, opaque envelopes.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation sequence will be generated using a computer-generated number list, using a block size of 20.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
None.
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
The aims of this study is to evaluate the efficacy of blue light filtering spectacle lenses in the treatment of computer vision syndrome (CVS). These lenses are currently prescribed in significant numbers, suggesting that practitioners believe the treatments are efficacious despite the lack of high-quality trial evidence supporting this. As much of the clinical assessment of CVS is symptom based, the potential for placebo effects is likely to be high.

Our study differs from a traditional double-masked trial in several important ways. In traditional double-masked clinical studies, participants are told that there is a 50% chance they will not receive the treatment, and the possible actions of the treatment are phrased in neutral language to avoid bias from the experimenter either advocating for, or expressing scepticism about, a treatment. It is likely that both of these factors (i.e. the participant knowing they may not have received the treatment, as well as the lack of advocacy for the treatment) acts to diminish placebo effects. Such trials stand in stark contrast to how blue light spectacles are actually prescribed: patients know unequivocally that they have received the treatment, and practitioners only provide the treatment because they actively believe it will help the patient. The potential for placebo effects are therefore much greater, and such placebo effects might underlie the perceived efficacy of the treatment in practice. In this study, we therefore aim to quantify the magnitude of how much practitioner advocacy can augment the response of patients to blue light filtering spectacle interventions, in patients who believe they have been administered the intervention.

Our study contains a placebo treatment (i.e. conventional spectacle lenses not designed to alleviate CVS), but all patients will be led to believe they have received an active treatment. The nature of this deception is therefore not described in the publicly visible documentation for the study, to prevent this deception being unmasked. In both the treatment and placebo groups, half of participants will be instructed (using a standardized script) that there is strong clinical impression that the treatment is effective, whereas the other half will be instructed that there is a strong clinical impression that the treatment is not effective. Our study design therefore allows us to simultaneously measure placebo effects (i.e. overall difference between treatment and placebo arm) as well as how practitioner advocacy influences CVS outcomes in patients who believe they have received a treatment (i.e. overall difference between advocacy verses non-advocacy arms).

Sample size calculation: A total of 120 participants (aged between 18 to 40 years) with CVS will be recruited. Initially, the sample size was calculated based on previously noted changes in detecting a significant difference in computer vision syndrome symptoms between the intervention and placebo groups. A power analysis (80% power for finding a 5% effect size) with an estimated effect size of 1.02 (based on previous study) and allowing for a potential attrition rate of 20%, we calculated that we needed sample size of 16 participants per group. However, as noted, the present study also considers whether a clinicians’ positive/negative advocacy of the intervention affects placebo and nocebo responses. Despite a comprehensive search of the literature, we could not identify a relevant reference to use as a basis for performing a formal sample size calculation for the deception component of this study (as little is known about the magnitude of the effect in the ocular domain). In this respect, the present study will be considered an exploratory study.

Data analysis: A three-way ANOVA will be performed to investigate the efficacy of the blue-light lenses and the effect of deception (positive and negative advocacy) by analysing: the within-group factors of pre- and post- task measurements, the between-group factor of deception (positive/negative) and the between-group factor of lens type (blue-light filtering versus control/placebo).

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
28/01/2019
Actual
14/03/2019
Date of last participant enrolment
Anticipated
31/01/2020
Actual
15/01/2020
Date of last data collection
Anticipated
Actual
15/01/2020
Sample size
Target
120
Accrual to date
Final
120
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment postcode(s) [1] 24418 0
3010 - University Of Melbourne

Funding & Sponsors
Funding source category [1] 300997 0
University
Name [1] 300997 0
The University of Melbourne
Country [1] 300997 0
Australia
Primary sponsor type
Individual
Name
Assoc. Prof. Andrew Anderson
Address
Department of Optometry and Vision Sciences
Level 4 – Alice Hoy Building (Bldg 162), Monash Road
The University of Melbourne
Parkville, Victoria, Australia 3010
Country
Australia
Secondary sponsor category [1] 300586 0
None
Name [1] 300586 0
Address [1] 300586 0
Country [1] 300586 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 301751 0
'University of Melbourne - Psychology health and applied sciences human ethics sub-committee
Ethics committee address [1] 301751 0
Ethics committee country [1] 301751 0
Australia
Date submitted for ethics approval [1] 301751 0
14/08/2018
Approval date [1] 301751 0
05/10/2018
Ethics approval number [1] 301751 0
1852643

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 87978 0
A/Prof Andrew Anderson
Address 87978 0
Department of Optometry and Vision Sciences
Level 4 – Alice Hoy Building (Bldg 162), Monash Road
The University of Melbourne
Parkville, Victoria, Australia 3010
Country 87978 0
Australia
Phone 87978 0
+61 390359916
Fax 87978 0
Email 87978 0
aaj@unimelb.edu.au
Contact person for public queries
Name 87979 0
Andrew Anderson
Address 87979 0
Department of Optometry and Vision Sciences
Level 4 – Alice Hoy Building (Bldg 162), Monash Road
The University of Melbourne
Parkville, Victoria, Australia 3010
Country 87979 0
Australia
Phone 87979 0
+61 390359916
Fax 87979 0
Email 87979 0
aaj@unimelb.edu.au
Contact person for scientific queries
Name 87980 0
Andrew Anderson
Address 87980 0
Department of Optometry and Vision Sciences
Level 4 – Alice Hoy Building (Bldg 162), Monash Road
The University of Melbourne
Parkville, Victoria, Australia 3010
Country 87980 0
Australia
Phone 87980 0
+61 390359916
Fax 87980 0
Email 87980 0
aaj@unimelb.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
As per the ethics only researchers named on this application will have access to the data.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseDo Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial.2021https://dx.doi.org/10.1016/j.ajo.2021.02.010
N.B. These documents automatically identified may not have been verified by the study sponsor.