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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
Type of registration
Prospectively registered

Titles & IDs
Public title
A comparison of the development of collateral blood vessels in participants with branch retinal vein occlusion and hemicentral retinal vein occlusion.
Scientific title
Retinal Vein Occlusion Study: Branch vs Hemicentral. A study to show whether hemi-central retinal vein occlusions (hemi-CRVO) resolve quicker and require less treatment with anti-VEGF injections by developing more haemodynamically efficient collateral circulation much earlier than branch retinal vein occlusions (BRVO).
Secondary ID [1] 292474 0
Nil known
Universal Trial Number (UTN)
Trial acronym
RVO Study.
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hemi-central retinal vein occlusion 304101 0
Branch retinal vein occlusion 304102 0
Condition category
Condition code
Eye 303436 303436 0 0
Diseases / disorders of the eye

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Optical Coherence Tomography Angiography (OCT-A) will be used to examine the vascular changes that occur at the sites of collateralisation in participants with a hemi-CRVO or a BRVO that has been treated using the standard conventional anti-VEGF treatments. OCT-A is a new, non-invasive imaging modality that is used to evaluate the retinal circulation. We will use the OCT-A images as well as the Fluorescein angiogram images (FA) taken from the participants medical records to determine the speed of development and the type of collateral circulation that develops. This study has only one visit, that will occur at least 3 months after the participant has been free of macula oedema from their conventional treatment. The number of anti-VEGF treatments that the participants have received will be compared to the development of the collateral vessels between the two groups.
Intervention code [1] 298662 0
Diagnosis / Prognosis
Comparator / control treatment
A comparison in the size and number of collateral vessels that form at the site of the blockage in patients who have received anti-VEGF treatment for BRVO and hemi-CRVO will be made at the study visit.
Control group

Primary outcome [1] 302819 0
To determine whether hemi-CRVOs develop more haemodynamically efficient collateral circulation compared to BRVOs.
Timepoint [1] 302819 0
Comparison of OCT-A images between the hemi-CRVO and BRVO groups taken at the study visit.
Primary outcome [2] 303267 0
To determine whether hemi-CRVO participants require less anti-VEGF treatment compared to BRVO participants.
Timepoint [2] 303267 0
The medical records of the participants will be reviewed to determine the number of anti-VEGF treatments each participant has received during their treatment phase prior to entry into the study.
Primary outcome [3] 303268 0
To compare the time it takes for the hemi-CRVOs to resolve compared to the BRVOs.
Timepoint [3] 303268 0
The medical records of the participants will be reviewed. The FA images taken during the participant's treatment (prior to entry into the study) will be used to determine how long it has taken for the occlusion to resolve in both study groups.
Secondary outcome [1] 337163 0
To quantify the size of collaterals in participants with Hemi-CRVO and BRVO by using OCT-A and FA images.
Timepoint [1] 337163 0
Analysis of OCT-A and FA images taken at the study visit.
Secondary outcome [2] 338483 0
To quantify the number of collaterals in participants with hemi-CRVO and BRVO by using OCT-A and FA images.
Timepoint [2] 338483 0
Analysis of the OCT-A and FA images taken at the study visit.

Key inclusion criteria
1. Dry macula for three months following anti-VEGF treatment.
2. Access to participants medical notes including Fluorescein angiograms (FA).
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Inability to fixate for OCT-A image acquisition.

Study design
Statistical methods / analysis
With a statistical significance of 95% and assuming that hemi-CRVO will resolve at twice the speed of the BRVO with half the number of injections of anti-VEGF; 21 participants are required in each arm. The analysis will include descriptive statistics for demographics and the main clinical data, and qualitative descriptions of the imaging characteristics. The mean number of injections required in each RVO group and the overall time for resolution of the macular oedema will be compared.

Recruitment status
Reason for early stopping/withdrawal
Participant recruitment difficulties
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 8570 0
Lions Eye Institute Day Surgery Centre - Nedlands
Recruitment hospital [2] 8571 0
Sir Charles Gairdner Hospital - Nedlands
Recruitment hospital [3] 8572 0
Royal Perth Hospital - Perth
Recruitment postcode(s) [1] 16676 0
6009 - Nedlands
Recruitment postcode(s) [2] 16677 0
6000 - Perth

Funding & Sponsors
Funding source category [1] 297046 0
Name [1] 297046 0
Lions Eye Institute
Address [1] 297046 0
2 Verdun St
Western Australia
Country [1] 297046 0
Primary sponsor type
Lions Eye Institute
2 Verdun St
Western Australia
Secondary sponsor category [1] 296420 0
Name [1] 296420 0
Address [1] 296420 0
Country [1] 296420 0

Ethics approval
Ethics application status
Ethics committee name [1] 298227 0
Sir Charles Gairdner and Osborne Park Health Care Group Human Research Ethics Committee
Ethics committee address [1] 298227 0
2nd Floor, A Block
Sir Charles Gairdner Hospital
Western Australia
Ethics committee country [1] 298227 0
Date submitted for ethics approval [1] 298227 0
Approval date [1] 298227 0
Ethics approval number [1] 298227 0

Brief summary
The aim of this study is to determine how effective the blood vessels (collateral vessels) are that develop around the area where the blockage (occlusion) occurred in patients who have had treatment for a branch retinal vein occlusion (BRVO) or a hemicentral retinal vein occlusion (Hemi-CRVO). The study visit will take place once the patient has been stable for 3 months requiring no anti-VEGF treatment for macula oedema. The duration and number of anti-VEGF treatments that participants have received during their treatment will be recorded. Fluorescein angiography (FA) and optical coherence tomography (OCT) images taken during the treatment will be used to determine how efficient the collateral circulation is that develops. We will also use a new imaging technique called optical coherence angiography (OCT-A) to examine the efficiency retinal circulation at the collateral sites. OCT-A is a non invasive imaging technique and takes about 45 minutes to complete.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 76402 0
Prof Ian McAllister
Address 76402 0
Lions Eye Institute
2 Verdun St
Western Australia
Country 76402 0
Phone 76402 0
+61 8 9381 0870
Fax 76402 0
+61 8 9381 0766
Email 76402 0
Contact person for public queries
Name 76403 0
Prof Ian McAllister
Address 76403 0
Lions Eye Institute
2 Verdun St
Western Australia
Country 76403 0
Phone 76403 0
+61 8 9381 0870
Fax 76403 0
+61 8 9381 0766
Email 76403 0
Contact person for scientific queries
Name 76404 0
Prof Ian McAllister
Address 76404 0
Lions Eye Institute
2 Verdun St
Western Australia
Country 76404 0
Phone 76404 0
+61 8 9381 0870
Fax 76404 0
+61 8 9381 0766
Email 76404 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
All participant data will be de-indentified and not linked to the participant.
Ethics approval did not include the release of individual participant data.
What supporting documents are/will be available?
Study protocol
Informed consent form
Ethical approval
How or where can supporting documents be obtained?
Type [1] 6362 0
Study protocol
Citation [1] 6362 0
Link [1] 6362 0
Email [1] 6362 0
Other [1] 6362 0
Attachment [1] 6362 0
Type [2] 6363 0
Informed consent form
Citation [2] 6363 0
Link [2] 6363 0
Email [2] 6363 0
Other [2] 6363 0
Attachment [2] 6363 0
Type [3] 6364 0
Ethical approval
Citation [3] 6364 0
Link [3] 6364 0
Email [3] 6364 0
Other [3] 6364 0
Attachment [3] 6364 0
Summary results
No Results