Diabetes is an increasing public health concern in the UK and worldwide. There are 2.9 million people diagnosed with diabetes in the UK and an estimated 850,000 people who have the condition but are not recognised. 

diabetic eye screening

All patients with diabetes are at risk of developing diabetic retinopathy. This condition is caused by damage to small blood vessels at the back of the eyes, which reduces the blood supply.  This stimulates the growth of fragile, new blood vessels in the eye, which may bleed and damage the retina, leading to sight loss. Every year, around 4,200 people in England are at risk of blindness caused by diabetic retinopathy, which leads to 1,280 people becoming blind. It is one of the most common causes of sight loss in the UK in the working population, which therefore leads to a large social and financial burden.

Early diagnosis and treatment can dramatically reduce the risk of blindness from diabetic retinopathy.  All people aged 12 years and older with type 1 or type 2 diabetes are offered diabetic retinopathy screening every year by the National Screening Programme.  The test involves the administration of eye drops, followed by a photograph being taken of the retina (without touching the eye). The rate of uptake of screening is 81% in the UK.  However, there is a lot of variation between different areas, with evidence of lower uptake in more socially deprived areas.  The effectiveness of the screening programme depends on whether people actually attend their appointments.  Therefore, it is important to discover simple, cost-effective ways to encourage people to attend their appointments.

It is likely that the reason for missing an appointment is not always as a result of an active choice, and weighing up the benefits and risks of attending. Often, those invited to attend simply forget about their appointment or else something else takes priority. One way of influencing health choices is to offer incentives. Amongst other health behaviours, financial incentives have been successfully used to help people quit smoking and to complete vaccination courses. Providing incentives in this context can be controversial but they can also be an effective way to achieve healthier behaviours, which can be cost-effective for the health services.

This study is testing whether different types of financial incentives can encourage people to attend diabetic eye screening.  The types of incentives used were based on insights from behavioural sciences. 


  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?

Design and status
Randomised controlled trial, UKCRN 18434.  The trial is funded by the NIHR Health Services and Delivery Research Programme.  The data collection is now completed and the data is being analysed.

People who had not attended screening for at least two years were included in the trial.  Participants were randomised to a control group, a fixed incentive group, or a lottery incentive group.  The control group received the standard appointment invitation letter.  The fixed group received a standard letter, including a ‘voucher’ for £10 if participants attend their appointment.  The lottery group received the standard letter, including a voucher promising entry into a prize draw with a 1 in 100 chance of winning £1000 if they attended their appointment. In total, 1051 participants were included in the study, 435 in the control group, 312 in the fixed incentive group, and 304 in the lottery incentive group. 

Outcome measures
The main outcome of the study will be testing whether incentives make people more likely to attend their eye screening appointment.  We will also investigate whether one type of incentive has a greater impact than the other, and whether incentives encourage certain demographic groups to attend, who otherwise are less likely to.   We will see whether the use of financial incentives is a cost-effective way to increase uptake of diabetic eye screening.


Trial partners 
Imperial College London1st Retinal Screen LimitedStretson University London School of Economics 
Mr Colin Bicknell   Lisa Bishop  Dr Laura Gunn (statistician)  Dr Derek King (health economist) 
 Professor Lord Ara Darzi   Grant Duncan     
 Dr Gaby Judah  Peter Tyacke     
 Dr Dominic King       
 Professor Jonathan Valabhji      
 Professor Ivo Vlaev      
Summary of the table's contents
NHS England Public Health EnglandPatient representative 
 Gemma Harris   Adrian Brown  Elizabeth Pigott
Summary of the table's contents