This was a study published in Diabetes Care. Turnover rate is defined as the rate at which macular microaneurysms appear and then disappear. This is justification for photographing carefully diabetics with any microaneurysms.
The study concluded:
microaneurysm (MA) turnover predicts development of clinically significant macular edema( CSME) in eyes with non proliferative diabetic retinopathy. Low MA turnover values identify well the eyes that are less likely to develop CSME in a 2-year period.