Microangiopathy is one of the most frequent and serious complications of diabetes. Its diagnosis is based on fundus of eye and fluorescein angiography findings, but several teams have emphasized the value of conjunctival angioscopy (CA) and peri-ungual capillaroscopy (PUC), describing suggestive anomalies: microectatic venous dilatation (V/A greater than 4.5), sludge on CA, "fish shoal" capillaries on PUC. Up to the present, however, the diagnostic value of these anomalies has not been evaluated based on data that are sensitive, specific and indicate predictive positive and negative values of a sign (Se, Sp, PPV, NPV). Anomalies of CA and PUC as a function of presence or absence of "diabetes" were studied in 114 patients with moderate hypertension, including 46 "diabetics" (33 with glucose regulation disorders and 13 non-insulin dependent diabetics). "Diabetes" was observed more predominantly in males of more advanced age and with a significantly higher global CA score (4.25 +/- 1.44 as against 2.65 +/- 1.35), and this in an increased manner as the "diabetes" was severe. Some anomalies had themselves a major orientation value with an Sp greater than 80% and an Se close to 40% (global score greater than 4; V/A greater than 4.5, microectasia, rheologic changes). For the fish shoal appearance the Sp was 73.5% and the Se 43.5%. The Sp was greater than 95% when at least 4 of the following 6 signs were present: global score greater than 4, V/A greater than 4.5, microectasia, rheologic disorders, fish shoal, gerontoxons. The more signs associated the more the Sp increased; the Se decreased from 40% for one sign to less than 10% for 4 associated signs.(ABSTRACT TRUNCATED AT 250 WORDS)