Digital retinal vessel imaging eliminates the need for injectable dyes, reducing patient discomfort and expanding access. Routine use of this more patient-friendly approach might also encourage early diagnosis. Ultra-widefield angiography (UWFA) can capture up to 200° of the fundus in a single image, well into the far periphery of the retina. Investigators suspect this capability can have broad implications for the diagnosis and management of diseases that may first be observable in the peripheral retina, such as diabetic retinopathy (DR).

To evaluate just how the technology can be used to understand the disease, a team of Cleveland Clinic researchers identified 339 eyes with DR that had undergone UWFA. They found that DR severity is associated with three parameters UWFA can help evaluate: panretinal leakage index, panretinal ischemic index and panretinal microaneurysm count.

Of the eyes tested, 11.2% had mild non-proliferative DR (NPDR), 23.9% had moderate NPDR, 40.1% had severe NPDR and 24.8% had proliferative DR (PDR). After dividing the three disease parameters by severity, the researchers found the mean panretinal leakage indices were 0.51% for mild NPDR, 1.20% for moderate NPDR, 2.75% for severe NPDR and 5.84% for PDR. Mean panretinal ischemic index was 0.95% for mild NPDR, 1.37% for moderate NPDR, 2.80% for severe NPDR and 9.53% for PDR.

Mild NPDR had a mean of 36 panretinal microaneurysm counts, moderate NPDR had 129, severe NPDR had 203 and PDR had 254. All were strongly associated with DR severity. In addition, DR severity was significantly correlated with patient age, as well as hemoglobin A1c values. Multivariate analysis demonstrated that ischemic index and leakage index were the parameters most strongly associated with level of retinopathy severity.