News and notices. Comm Eye Health Vol. 28 No. 92 2015. April 15, 2016

Online training for DR grading


Detection and assessment of diabetic retinopathy (DR) is not a simple task. Most people who are screened for diabetic retinopathy are found not to be affected, which can make grading the many ‘normal’ cases a tiring repetitive process. When retinopathy is found, there are many different lesions or features to detect and recognise. Some of the earliest (e.g. microaneurysms) and the potentially most severe (e.g. new vessels) are very small and difficult to detect reliably. All the features are however very important and therefore grading DR requires knowledge, skill, patience and great attention to detail.

Test & Training (TAT) is an online system for graders of DR who work in systematic diabetic eye screening programmes. The system, which is delivered online, is currently used by grading staff who work in the English NHS Diabetic Eye Screening Programme.

Seeing is Believing (SiB) has given the developers of TAT a US $50,000 grant to develop an international version (iTAT) which has been piloted in three countries: Bangladesh, Indonesia and Botswana. A further grant has recently been given to broaden it out to more countries.

TAT and iTAT use a common series of retinal images from patients with diabetes who have consented to have their images used for professional training and education. Each month, graders access sets of retinal images from 20 eyes and identify and record the retinopathy features present in the set of previously ‘ground-truth’ classified images. Each set of 20 cases is randomised at the point of delivery, so no two people see cases in exactly the same order. The user can magnify the retinal image, view it as red-free or greyscale and alter the contrast and brightness; all helping them to come to a decision on the presence and severity of retinal lesions. An example from the grading form and image viewer is shown below as Figure 1.

The system records the user’s responses as they identify a lesion (such as microaneurysms or exudate) and compares those with the pre-graded results for that case, in order to calculate an overall percentage accuracy score for the set of 20 cases. Following the end of each month, the user can access more detailed information on their performance and can also access the images again but with the added advantage of having each different lesion or feature of DR already annotated as an ‘overlay’ on the image. These annotations are each selectable ‘on/off’ by the user, so enabling them to clearly see the underlying pathology in the images, further enhancing their learning experience.

Both TAT and iTATA require access to the internet in order to function. The developers hope that, with continuation of grant funding, they will be able to identify a more robust method of long-term access to the internet for iTAT in some areas where this is a major problem.

Access to iTAT is free at the SiB-supported sites, and elsewhere a fee is payable. More information is available at

News and notices in Comm Eye Health Vol. 28 No. 92 2015 –