Condition category
Eye Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
One of the most common complications of diabetes is diabetic retinopathy. This disease can cause vision loss when fluid accumulates inside the eye (known as diabetic macular oedema, DMO) and when new blood vessels grow in the eye (proliferative diabetic retinopathy, PDR). There are ever increasing numbers of people with DMO and PDR: as many as 220,000 people in the UK are thought to have DMO and 212,000 believed to have PDR. Once patients are treated, long term follow up is required for the rest of the patients’ life. Currently in the UK an ophthalmologist will review a patient at each appointment to determine if they still have active disease in their eyes. Given the high numbers of patients with DMO and PDR and the need for patients to be seen at short follow-up intervals for long-term follow up it is becoming difficult for the NHS to cope with demand. The aim of this study is to assess whether a patient who has been previously successfully treated for DMO/PDR could be reviewed and assessed without a face-to-face consultation with an ophthalmologist. The study investigates whether trained ophthalmic graders (healthcare professionals who have many years’ experience taking images of the back of the eyes) can interpret the photographs of the back of the patients’ eyes with the same accuracy that an ophthalmologist can.

Who can participate?
Patients aged 18 or older with type 1 or 2 diabetes with previously successfully treated DMO and/or PDR in one or both eyes (DMO and/or PDR may be active or inactive at the time of the study)

What does the study involve?
Each participant attends their normal clinic appointment and goes through the standard eye tests they normally do at each visit. The ophthalmologist evaluating them determines whether active/inactive DMO/PDR is present. The participants then have two more sets of photographs taken of the back of their eyes and are asked to fill in some questionnaires. There are no follow-up visits required and the extra tests should only add around 20 minutes extra to the patients’ visit. Some patients are asked if they would like to take part in some discussions where they can share their views on the new care pathway. These happen at a later date.

What are the possible benefits and risks of participating?
Participating will help to determine whether other health professionals besides doctors could look after people that have been treated for the complications of diabetes in the eye once they are considered to be stable. If this is the case, this will relieve doctor’s time in the NHS and doctors could then see patients with active disease and who require treatment more promptly. This may help with waiting times in the NHS. If the study shows that having other health professionals seeing patients once they are stable is not as good as having eye doctors evaluating them, then this strategy will not be used in the NHS. There are no risks associated with the study. Taking photographs of the back of the eyes has no known side effects.

Where is the study run from?
1. The Royal Hospitals (UK)
2. Gloucestershire Hospitals (UK)
3. Central Manchester University Hospitals (UK)
4. Bristol Eye Hospital (UK)
5. Bradford Teaching Hospitals - Bradford Royal Infirmary (UK)
6. Sunderland Eye Infirmary (UK)
7. Queen Margaret Hospital (UK)
8. Moorfield Eye Hospitals (UK)
9. Sheffield Teaching Hospitals (UK)
10. King’s College Hospital (UK)
11. Frimley Park Hospital (UK)
12. Oxford Eye Hospital (UK)

When is the study starting and how long is it expected to run for?
April 2017 to October 2019

Who is funding the study?
Health Technology Assessment Programme (UK)

Who is the main contact?
1. Dr Sorcha Finnegan (public)
2. Prof. Noemi Lois

Trial website

Contact information



Primary contact

Dr Sorcha Finnegan


Contact details

Northern Ireland Clinical Trials Unit
1st Floor Elliott Dynes Building
Royal Hospitals
Grosvenor Road
BT12 6BA
United Kingdom
+44 (0)28 9063 5794



Additional contact

Prof Noemi Lois


Contact details

The Wellcome-Wolfson Institute for Experimental Medicine
School of Medicine
Dentistry and Biomedical Sciences
Queen's University Belfast
97 Lisburn Road
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

HTA 15/42/08; IRAS 227551

Study information

Scientific title

Effectiveness of Multimodal imaging for the Evaluation of Retinal odema And new vesseLs in Diabetic retinopathy: a diagnostic accuracy study



Study hypothesis

The new form of surveillance for people with stable diabetic macular odema (DMO) and/or poliferative diabetic retinopathy (PDR) will be as sensitive as the current standard of care but at a lower cost.

Ethics approval

Office for Research Ethics Committees Northern Ireland (ORECNI) - approval pending

Study design

Prospective cross-sectional diagnostic accuracy study

Primary study design


Secondary study design

Cross sectional study

Trial setting


Trial type


Patient information sheet

See additional files


1. Proliferative diabetic retinopathy (PDR)
2. Diabetic macular odema (DMO)


EMERALD has a case-referent cross-sectional diagnostic study design with both sampling (selection) of patients and data collection carried out prospectively.

Multimodal retinal imaging with subsequent review of the images by trained ophthalmic graders (new pathway) will be compared with current standard of care (ophthalmologist examining patients in clinic with imaging tests used in current practice).

Patients with previously successfully treated DMO/PDR will attend the clinic, as per standard practice, and the following will be undertaken:
1. Visual acuity testing
2. OCT
3. Fundus examination
The ophthalmologist evaluating them will confirm eligibility, obtain informed consent, and determine whether active/inactive DMO/PDR is present (reference standard).

In addition the patients will then undergo wide angle fundus imaging and 7 field ETDRS fundus imaging (index test). There is no follow up for patients – a single visit is all that is required.

Intervention type



Drug names

Primary outcome measure

Sensitivity of the new pathway (ophthalmic grader pathway) in detecting active DMO/PDR is assessed by evaluating the Case Report Forms (CRFs) at baseline

Secondary outcome measures

1. Specificity, concordance (agreement) between the new pathway (ophthalmic grader pathway) and the standard care pathway, positive and negative likelihood ratios are assessed by evaluating the CRFs at baseline
2. Cost-effectiveness is assessed by evaluating the CRFs and the EQ-5D questionnaire at baseline
3. Acceptability is assessed by evaluating the Focus Group Discussion feedback at baseline
4. Proportion of patients requiring subsequent full clinical assessment is assessed by evaluating the CRFs at baseline
5. Proportion of patients unable to undergo imaging, with inadequate quality images or indeterminate findings, is assessed by evaluating the CRFs at baseline

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Adults (18 years of age or older)
2. Type 1 or 2 diabetes
3. Previously successfully treated DMO and/or PDR in one or both eyes and in whom, at the time of enrolment in the study
4. DMO and/or PDR may be active or inactive
4.1. Active DMO will be defined as a central subfield retinal thickness (CRT) of > 300 microns and/or presence of intraretinal/subretinal fluid on spectral domain OCT
4.2. Inactive DMO will be defined as a CRT of <300 microns and no intraretinal/subretinal fluid
4.3. Active PDR will be defined by the presence of sub-hyaloid/vitreous haemorrhage and/or active new vessels (new vessels with lack of fibrosis on them)
4.4. Inactive PDR will be defined by the lack of preretinal/vitreous haemorrhage and lack of active new vessels

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Unable to provide informed consent
2. Patients do not read, speak or understand English

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

The Royal Hospitals Belfast
BT12 6BA

Trial participating centre

Gloucestershire Hospitals

Trial participating centre

Central Manchester University Hospitals
M13 9WL

Trial participating centre

Bristol Eye Hospitals

Trial participating centre

Bradford Teaching Hospitals

Trial participating centre

Sunderland Eye Infirmary

Trial participating centre

Queen Margaret Hospital
KY12 0SU

Trial participating centre

Moorefield Eye Hospitals

Trial participating centre

Sheffield Teaching Hospitals
S10 23F

Trial participating centre

King's College Hospital

Trial participating centre

Frimley Park Hospital
GU16 7UJ

Trial participating centre

Oxford Eye Hospital

Sponsor information


Belfast Health and Social Care Trust

Sponsor details

Research Governance
King Edward Building
Belfast Health and Social Care Trust
Royal Victoria Hospital Site
Grosvenor Road
BT12 6BA
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Results and Publications

Publication and dissemination plan

The protocol has not yet been published online but will be made available at some stage.

It is anticipated that the study findings will be published in national and international peer reviewed journals approximately November 2020 and these articles will be led by the CI. This will secure a searchable compendium of these publications and make the results readily accessible to the public and healthcare professionals. In addition, study findings may be presented at both national and international meetings and to appropriate patient groups.

A report containing the methodology and results of this diagnostic study will be published as a Health Technology Assessment monograph, freely accessible via the NIHR HTA webpage. The Royal College of Ophthalmologist will be contacted once the study is completed to allow the trial’s findings to be incorporated in future Diabetic Retinopathy guidelines.

IPD sharing statement
Requests for data sharing will be reviewed on a case by case basis by the CI (Prof. Noemi Lois) and TMG. Following the publication of the primary and secondary outcomes, there may be scope to conduct additional analyses on the data collected. In such instances, formal requests for data will need to be made in writing to the CI who will discuss this with the TMG. In the event of publications arising from such analyses, those responsible will need to provide the CI with a copy of any intended manuscript for approval prior to submission. Authorship will need to take the format of “[name] on behalf of the EMERALD Clinical Trial Group” or something similar, which will be agreed by the TMG.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes