Measuring the Foveal Avascular Zone in Diabetes: a Study Using Optical Coherence Tomography Angiography.

INTRODUCTION Diabetes is a global issue that currently affects 425 million people worldwide. One observable microvascular complication of this condition is a change in the foveal avascular zone (FAZ). In this study, we used optical coherence tomography angiography (OCT-A) to investigate the effect of diabetes on the FAZ. MATERIALS AND METHODS Eleven diabetic and eleven non-diabetic participants took part in this study. Participants in both groups were matched for age (p = 0.217) and sex (p = 0.338), and had no history of ocular disease. Macular OCT-A scans of participants' right and left eyes were taken. Glycosylated haemoglobin (HbA1c ) and blood glucose levels were also measured. The FAZ area was manually segmented at the levels of the superficial capillary plexus (FAZSCP ) and deep capillary plexus (FAZDCP ). RESULTS There was a strong relationship between the FAZ area of participants' right and left eyes (p ≤ 0.001) in both diabetic and non-diabetic groups. In the diabetic group, the FAZSCP (p = 0.047) and FAZDCP (p = 0.011) areas was significantly larger than in the non-diabetic group. Moreover, multiple linear regression analysis predicted a 0.07-mm2 increase in diabetic individuals' FAZSCP and FAZDCP areas for every 1% increase in their HbA1c level. CONCLUSIONS Our findings indicate that there is enlargement of the FAZ in diabetic individuals compared with non-diabetic individuals. In the diabetic group, this enlargement appears to be correlated with HbA1c level. OCT-A imaging could, therefore, be a useful tool to monitor the FAZ and identify potential early microvasculopathy in diabetes.