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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Retrospectively registered

Titles & IDs
Public title
Contact lens to enhance blood flow for ischemic eye diseases
Scientific title
The effect of retinal image defocus on choroidal blood flow in healthy young adults
Secondary ID [1] 293219 0
Universal Trial Number (UTN)
Trial acronym
Defocus and choroidal blood flow
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Ischemic retinal diseases 305236 0
Condition category
Condition code
Eye 304541 304541 0 0
Diseases / disorders of the eye

Study type
Description of intervention(s) / exposure
Name: Defocussing contact lens
Rationale: A defocussing contact lens (that would produce 2.00D myopic defocus) will be applied to the experimental eye for approximately 40 minutes prior to the MRI scan. Previous studies have shown that the application of contact lens inducing myopic defocus causes an increase in choroidal thickness, which is maximum at this time point.
Materials: CooperVision 54% 1-day Silicone Hydrogel;
Procedures: The trial will consist of two visits for each participant. In one of the visits, both eyes will be fully corrected with contact lenses of appropriate power, whereas, in the other, one randomly chosen eye (experimental eye) will be subjected to myopic defocus. The order of the experimental condition (i.e. defocus/no defocus) will be randomized between the two visits. Following the application of contact lens for 40 minutes, MRI will be performed in order to obtain measures of choroidal blood flow in both eyes.
Personnel: A research optometrist with an optometry qualification (Doctor of Optometry degree) will be responsible for patient recruitment, eye examination, and providing intervention. MRI scans will be performed by MRI technologists experienced with perfusion MRI.
Mode: Intervention (+2.00D defocussing contact lens) will be given individually to the research participants only once on the study visit
Where: The trial will be conducted in School of Optometry and Vision Science and the Centre for Advanced MRI at the University of Auckland
Intervention code [1] 299478 0
Treatment: Devices
Comparator / control treatment
This study has a within-subject design- the contralateral eye of each participant will serve as the control., which will be fully corrected with contact lenses of appropriate power during the experiment.
Control group

Primary outcome [1] 303792 0
Choroidal blood flow in ml/100gm/min, as measured with Magnetic Resonance Imaging
Timepoint [1] 303792 0
Two visits (before and after defocus) within a week
Secondary outcome [1] 340164 0
Choroidal thickness in micrometers, as measured by Optical Coherence Tomography
Timepoint [1] 340164 0
Two visits (before and after) within a week

Key inclusion criteria
18-35 years old healthy subjects
normal or corrected to normal vision with glasses/contact lenses
Minimum age
18 Years
Maximum age
35 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Refractive error greater than -3.00DS or +3.00D spherical equivalent with the difference between eyes more than 1.00D; astigmatism greater than 1.00D; amblyopia, any underlying ocular pathology or previous history of ocular surgery; and previous history of myopia control treatment (such as Ortho-K and atropine).

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
One randomly selected eye of each participant will serve as the experimental eye, while the contralateral eye will serve as the control eye.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Paired t-test will be used to compare changes in choroidal blood flow between the experimental and the control eyes. The within subject variance of the change in choroidal blood flow from our preliminary study had a standard deviation of 8.38 units. In order to obtain a power of 90% at a p-value of 0.01, 16 participants would be required to detect a difference in blood flow change between experimental and control eyes. Assuming a drop-out rate of 20%, we therefore aim to recruit 20 participants.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 9323 0
New Zealand
State/province [1] 9323 0

Funding & Sponsors
Funding source category [1] 297847 0
Commercial sector/Industry
Name [1] 297847 0
CooperVision Inc.
Address [1] 297847 0
6150 Stoneridge Mall Rd #370, Pleasanton, CA 94588, USA
Country [1] 297847 0
United States of America
Funding source category [2] 297869 0
Name [2] 297869 0
New Zealand Optometric Vision Research Foundation
Address [2] 297869 0
7 Bay Road
Wellington 6022
Country [2] 297869 0
New Zealand
Primary sponsor type
The University of Auckland
School of Optometry and Vision Science
The University of Auckland
85 Park Road, Grafton, Auckland
New Zealand

New Zealand
Secondary sponsor category [1] 296933 0
Name [1] 296933 0
Dr John Phillips
Address [1] 296933 0
School of Optometry and Vision Science
The University of Auckland
85 Park Road, Grafton 1023
Country [1] 296933 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 298894 0
University of Auckland Human Participants Ethics Committee
Ethics committee address [1] 298894 0
Level 10, Building 620
49 Symonds Street
Ethics committee country [1] 298894 0
New Zealand
Date submitted for ethics approval [1] 298894 0
Approval date [1] 298894 0
Ethics approval number [1] 298894 0

Brief summary
Retinal ischemia plays a significant role in the pathogenesis of age-related macular degeneration (AMD) and diabetic retinopathy (DR)- two of the most common sight-threatening diseases in the developed world. Treatment options for these conditions are limited and there is a significant interest in developing methods for increasing ocular blood flow so as to reduced ischemia and inhibit disease progression. In healthy eyes, 70% of blood flow passes through the ocular choroid but in both AMD and DR the thickness of the choroid is significantly reduced. Interestingly, the choroid has a remarkable capacity to increase its thickness when exposed to short-term myopic defocus- a condition in which the image is formed in front of the retina. Because the choroid is largely a vascular tissue, this rapid and transient choroidal response to defocus is presumably driven by changes in blood flow. This project aims to translate this finding into a clinical application, and use contact lens-induced retinal defocus as a potential new treatment to increase choroidal thickness and blood flow in patients with AMD and DR so as to reduce ischemia and improve visual outcomes.

The primary purpose of the study is to investigate whether the application of defocussing contact lens enhances blood flow in the posterior eye. We hypothesize that a short-term wear of defocussing contact lens, known to produce thickness changes in the posterior eye, results in an increase in blood flow.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 2151 2151 0 0
/AnzctrAttachments/373882-Ethics_approval.pdf (Ethics approval)
Attachments [2] 2153 2153 0 0
/AnzctrAttachments/373882-CF_ChBFstudy.pdf (Participant information/consent)

Principal investigator
Name 78586 0
Dr John Phillips
Address 78586 0
School of Optometry and Vision Science
The University of Auckland
85 Park Road, Grafton
Country 78586 0
New Zealand
Phone 78586 0
+64 9 9236073
Fax 78586 0
Email 78586 0
Contact person for public queries
Name 78587 0
Dr Safal Khanal
Address 78587 0
School of Optometry and Vision Science
The University of Auckland
85 Park Road, Grafton
Country 78587 0
New Zealand
Phone 78587 0
+64 9 9237869
Fax 78587 0
Email 78587 0
Contact person for scientific queries
Name 78588 0
Dr John Phillips
Address 78588 0
School of Optometry and Vision Science
The University of Auckland
85 Park Road, Grafton
Country 78588 0
New Zealand
Phone 78588 0
+64 9 9236073
Fax 78588 0
Email 78588 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
De-identified data on all outcome measures
When will data be available (start and end dates)?
August 2019 to August 2020
Available to whom?
Researchers upon reasonable request
Available for what types of analyses?
Re-plotting and sub-analysis
How or where can data be obtained?
Shared drive
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary