ANZCTR - Registration

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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 information initially 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]

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

Condition category

Condition code

Eye

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]

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]

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]

Change in visual fatigue score pre and post 2-hours of computer task

Primary outcome [2]

Critical flicker frequency - measured using a custom-built light emitting diode-based stimulus

Timepoint [2]

Change in critical flicker frequency measurement pre and post 2-hours of computer task.

Secondary outcome [1]

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]

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]

Eye movements – measured using a saccadometer (Ober Consulting, Poznan, Poland) instrument.

Timepoint [2]

Change in eye movements, pre and post 2-hours of computer task.

Secondary outcome [3]

Near point of convergence quantified using the push-up method.

Timepoint [3]

Change in near point of convergence pre and post 2-hours of computer task.

Secondary outcome [4]

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]

At the end of the of the 2-hour computer task.

Secondary outcome [5]

Near point of accommodation quantified using the push-up method.

Timepoint [5]

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]

3010 - University Of Melbourne

Funding & Sponsors

Funding source category [1]

University

Name [1]

The University of Melbourne

Address [1]

Monash Rd, Parkville VIC 3052

Country [1]

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]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

'University of Melbourne - Psychology health and applied sciences human ethics sub-committee

Ethics committee address [1]

Office for Research Ethics and Integrity, The University of Melbourne, 1/21 Bedford St, North Melbourne VIC 3051

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

14/08/2018

Approval date [1]

05/10/2018

Ethics approval number [1]

1852643

Summary

Brief summary

Computer vision syndrome is defined as a group of eye and vision related problems that result from prolonged computer, tablet, e-reader or cell phone use. Its prevalence ranges from 75% to 90% among computer users. The most common ocular symptoms associated with computer vision syndrome are visual fatigue, followed by blurred vision, and dry eyes; these symptoms occur immediately, or after several hours of computer use. Recently, spectacle lenses have been introduced into the clinical practice with an aim to alleviate symptoms of computer vision syndrome. However, there are currently no high quality clinical trials that have investigated the efficacy of these lenses for the treatment of computer vision syndrome. Hence, this project comprises of series of experiments to scientifically investigate whether these spectacle interventions affect signs and symptoms of computer vision syndrome.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

A/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

Phone

+61 390359916

Fax

[email protected]

Contact person for public queries

Name

A/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

Phone

+61 390359916

Fax

[email protected]

Contact person for scientific queries

Name

A/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

Phone

+61 390359916

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

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

Type	Is Peer Reviewed?	DOI	Citations or Other Details	Attachment
Study results article	Yes		Singh S, Downie LE, Anderson AJ. Do Blue-blocking ... [More Details]

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial.	2021	https://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.

Trial Review

Documents added manually

Documents added automatically