Performance of EArly Retinal Laser (PEARL)

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Diabetes, an illness in which the body cannot manage blood sugar safely, is often thought of as a disease of wealth. In fact, over 80% of diabetes occurs in poor or middle-income countries, where rates are growing very quickly. In China, there is ten times more diabetes now than there was 30 years ago, and rates (12%) exceed the US. Over years, diabetes damages blood vessels and vision cells in the eye, and can cause blindness. Most diabetic blindness can be prevented with laser if caught early, but only 10% of rural diabetic persons in China receive care. A major reason is that standard treatment of diabetic eye disease ("DR") calls for patients to return for examinations until their eyes reach a late stage called "PDR", which may take many years, before any treatment is given. This can be very difficult for rural patients, who are often less educated and poorer, meaning they drop out before receiving care.We have completed a review of papers written about earlier treatment of DR, at a stage called "No PDR" or "NPDR." This review showed studies are needed to prove that this approach is safe and beneficial, but evidence suggests that early treatment could be better to preserve vision, and easier for patients who might otherwise drop out of standard care. To fill the gap in evidence, we designed a study where patients with disease at an earlier stage ("NPDR," the Early Group) get laser treatment right away in one eye chosen by chance and the other eye only get laser if "PDR" develops later, which is the current standard. We will compare eyes treated at NPDR and PDR stages for several outcomes important to patients: vision, developing more serious "PDR" disease, and damage to the eye from treatment. An important goal of this study is to find out if patients who get early treatment are less likely to drop out of follow-up. Since one eye of a patient can't "drop out," we will also have a second group of people who will get later treatment in both eyes only if PDR develops ("Standard Group"). We will compare the rate of dropout between the Early and Standard group. The cost of Early versus Standard treatment will also be examined.An equal number of urban and rural patients will be recruited, because our early work shows that rural patient are at special risk for dropping out, because of their lack of understanding of their disease, but we want to understand patients from both settings. Our study will have two main aims:1. This kind of study, a "trial," is expensive and hard. We want to first do a small "Pilot" (100 patients each in Early and Standard groups, versus 300 in each for the main trial) to show that we can find enough patients, convince them to join the study, give them the treatment as selected by chance, follow them for 1 year and collect necessary data.2. Care of DR in rich settings often depends on expensive tests or advanced training to define the stages ("NPDR," "PDR") and complications of treatment that require further care. Such tests and training may not be practical in poorer settings. In our study, trained local doctors will define stages and find complications using simple, cheap examinations. We will compare their results against more expensive tests and photo grading by experts to find out how well this simpler and cheaper approach works. Finding out if these locally appropriate ways work is very important for diabetic eye are in poorer areas, and will be an important part of our Pilot study.Our team includes Chinese and UK experts in diabetic eye care, statistics and trials such as this one. Patients will be recruited at the First Affiliated Hospital in Guangzhou, which has one of the largest diabetic clinics in China, and treated at Zhongshan Ophthalmic Hospital (ZOC), China's largest eye hospital. The main investigator, Prof Congdon, is an eye doctor based now in the UK, who has worked in China at ZOC for many years, is fluent in Chinese, and will help to link teams