Structural and functional changes among diabetics with no diabetic retinopathy and mild non-proliferative diabetic retinopathy using swept-source optical coherence tomography angiography and photopic negative response.

A significant decrease in functional changes as measured by ERG especially PhNR, is seen even among the NDR group compared to controls unlike SSOCTA parameters that measures very early vascular structural changes. PhNR is a sensitive test to identify early preclinical changes in DR when microvascular structural changes as determined by SSOCTA are normal.