Biomicroscopy versus fluorescein angiography of the iris in the detection of diabetic iridopathy.

Iris fluorescein angiography is not commonly employed in clinical practice, but it is the most sensitive technique for the evaluation of iris vessel abnormalities. We used iris fluorescein angiography as the gold standard against which to test the ability of iris biomicroscopy to demonstrate diabetic iridopathy (DI). One hundred and fourteen eyes of 63 diabetic patients affected by preproliferative or proliferative diabetic retinopathy (DR) (the DR groups at high risk of developing DI) were considered. The DI fluorangiographic classification used was: (1) absence of DI; (2) nonproliferative DI; (3) proliferative DI. The sensitivity of biomicroscopy in detecting DI turned out to be 57%, while the specificity was 94%. The positive predictive value was 93% and the negative predictive value 50%. Our study proved that biomicroscopy can accurately judge when DI is absent. When it is present, however, there is a high probability that biomicroscopy will be less precise in the detection of iris lesions.