Condition category
Eye Diseases
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Diabetes is becoming an increasing health problem around the world. People with diabetes are at risk of sight loss, from a condition called diabetic retinopathy. This happens when tiny blood vessels in the eye bleed, which destroys the retina. It is estimated that in England every year 4,200 people are at risk of blindness caused by diabetic retinopathy and there are 1,280 new cases of blindness caused by diabetic retinopathy. Once people experience symptoms, the disease is already advanced and may be difficult to treat, however, with early diagnosis and treatment, the risk of blindness can be dramatically reduced. In order to prevent avoidable blindness in people with diabetes, eye screening is essential. People with diabetes are invited to eye screening appointments every year. However, rates of attendance at these appointments vary between different areas, and those with the highest risk of sight damage are also those with lowest levels of attendance at screening appointments. The NHS needs simple, inexpensive and cost effective strategies are required by the NHS to influence health behaviours (for example, to increase the number of people attending screening programmes). This has relevance to diabetic eye screening but also more widely as the NHS increasingly tries to prevent disease rather than simply treat it. This study is looking at the impact of different types of financial incentives on encouraging people with diabetes to attend their eye screening appointments. The incentives being tested are a £10 reward, or being entered into a lottery to win £1000.

Who can participate?
People aged sixteen and over with diabetes, who have been invited to eye screening appointments in the past but who have not attended, or tried to rearrange their appointment.

What does the study involve?
People who are eligible for the study are randomly allocated to one of three groups. Participants in the first group (the control group) receive the usual letter, inviting them to an eye screening appointment. Participants in the second group are sent an appointment letter also offering them £10 if they attend their appointment. Participants in the third group are sent an appointment letter, also offering them the opportunity to be entered into a lottery for £1000 if they attend their appointment. The screening procedure involves drops being put into the eye, and a photograph being taken of the eye.

What are the possible benefits and risks of participating?
The benefit of participating is that if a participant is developing diabetic retinopathy, the screening can detect it early, so it can be treated to prevent it leading to blindness. Risks include the eyes being more sensitive to sunlight immediately after the screening procedure and participants should not drive after the appointment, as the drops may affect vision for a short time.

Where is the study run from?
The study is run from the Diabetic Eye Screening Programme managed by 1st Retinal Screen Ltd. There are two screening locations in London, one in Chelsea and Westminster Hospital, and one in St Marys Hospital.

When is the study starting and how long is it expected to run for?
May 2014 to August 2016

Who is funding the study?
National Institute for Health Research (UK)

Who is the main contact?
Mrs Gaby Judah

Trial website

Contact information



Primary contact

Mrs Gaby Judah


Contact details

Imperial College London
Division of Surgery
10th Floor
QEQM Building
St Mary's Campus
Praed Street
W2 1NY
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

REC 14/LO/1779

Study information

Scientific title

Incentives in Diabetic Eye Assessment by Screening (IDEAS) Trial



Study hypothesis

1. Are incentives an effective strategy to encourage participation in the screening programme?
2. Does the design of the financial incentive scheme affect its effectiveness in influencing participation in health screening?
3. Does the choice of incentive scheme, if successful, attract patients who have a different demographic or socioeconomic status to those who attend screening regularly?
4. Is offering these incentives a cost-effective strategy for enhancing participation?

Ethics approval

National Research Ethics Committee (London - Riverside), 14/10/2014, ref: 14/LO/1779

Study design

Single centre randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Diabetic retinopathy


Participants are randomly allocated to one of three groups:
Group 1 – Control Group: Standard invitation letter from the Screening Service .
Group 2 – Fixed Incentive: Standard invitation letter but with additional text offering a financial incentive (£10) after screening is completed.
Group 3 – Probabilistic Incentive: Standard invitation letter but with additional text offering a financial incentive (lottery offering 1% chance to win £1000).

Intervention type



Drug names

Primary outcome measure

Attendance at the screening appointment. This will be recorded at the appointment (which takes place four weeks after the invitation letter is sent), by the screener entering the patient into the electronic appointment record database. Following the end of data collection a search will be conducted on the database to extract information on attendance, as well as other demographic variables, and information on rearranged appointments.

Secondary outcome measures

1. Assess which incentive scheme is most effective
2. The cost effectiveness of different incentives on increasing uptake.
3. The impact on equity - whether incentives may encourage different groups to attend screening that may otherwise have not. A measure of social deprivation status will be calculated from the postcode. The impact of distance from the screening centre and GP practice will aslo be considered.
4. The effect of the different interventions on the number of participants who actually consent to the screening procedure once they attend the screening clinic

1st Retinal Screen Ltd will provide the anonymised data including the cohort’s age, gender, deprivation status (calculated from postcode), and ethnicity (subject to availability). The data will be provided following the screening of all participants.

If there are significant differences in screening uptake and the demographic/risk factor profile between incentive schemes then a more detailed calculation of the impact of incentives is planned.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Patients, aged 16 and older, who were invited to screening in the last 24 months on a yearly basis and failed to attend or contact the screening service to rearrange an appointment will be studied.

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Participants under the age of 16
2. Participants who have attended screening appointments in the past, or contacted the service to rearrange an appointment

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

1st Retinal Screen Ltd
W2 1NY
United Kingdom

Sponsor information


Imperial College London

Sponsor details

Division of Surgery
10th Floor
QEQM Building
St Mary's Campus
Praed Street
W2 1NY
United Kingdom

Sponsor type




Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Results and Publications

Publication and dissemination plan

The findings from this study will be disseminated to NHS Diabetic Eye Screening Programme, local stakeholders, and other NHS screening organisations through briefs/newsletters and working paper documents. The findings will be shared with the screening service commissioners NHS England (the commissioners may like to have input into who the findings are shared with).

The trial management group will be responsible for drafting the main reports from the study. Draft copies of any manuscripts will be provided to the Kensington, Chelsea and Westminster Diabetic Eye Screening Programme for review prior to publication.

The main findings will be submitted for publication in peer-reviewed scientific journals and presented in national and international conferences, such as the Annual Meeting & Exposition of the American Public Health Association, and the UK Faculty of Public Health. We will assess both the effectiveness and cost-effectiveness of our financial incentives on uptake to diabetic Eye Screening. We will provide updated information concerning the publication of trial results on a trial-related Web site linked to the trials unit home page. Specialist diabetes and non-specialist practitioners will be targeted, for example through national society conferences and newsletters. The trial results will, in particular, be shared with the National screening committee. The study results will also be presented to healthcare commissioners and policy makers at appropriate meetings and publications. A summary of results, in language appropriate for lay persons, will be sent to all relevant patient groups.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

2016 protocol in:
2017 results in:

Publication citations

Additional files

Editorial Notes

05/04/2017: Publication reference added. 21/03/2016: Publication reference added.