The objective of the work was to assess whether in patients with IDDM without signs of diabetic retinopathy changes in the sensitivity function to contrast (CS) develop as compared with a group of healthy subjects matched for age but also as a result of the persistence of IDDM or the level of its long-term compensation investigated by means of glycated haemoglobin (HbA1c). CS was examined by the static method using a VCTS 6500 table from a distance of 208 and 420 cm which covered the spatial frequencies from 1.15 to 27.25 c/st. Moreover the authors assessed the best correctable central visual acuity on Snellen´s optotypes, the ophthalmoscopic finding on the fundus with a colour photograph, fluorescein angiography and the HbA1c serum level. A group of 49 patients with IDDM was divided into two age groups: A(under 35 years), B (35 years and above). A marked decline ofthe CS function occurs in all spatial frequencies in both age groups. On comparison of the persistence of IDDM in group B no significant difference was found in CS, while in group A statistical significance was revealed in spatial frequencies 4 and 27,25 c/st. On comparison of the CS function in diabetics with a normal and pathological HbA1c level it was found that long-term hyperglycae- mia has not a marked effect on visual functions. Conclusion: The decline of CS in patients with IDDM without signs of diabetic retinopathy is influenced in particular by the patient´s age, in junior patients also by the persistence of IDDM. Examination of the CS is a simple non-invasive method suitable for screening of early affections of the eyes in IDDM

        Key words: diabetes mellitus (IDDM), contrast sensitivity, glycated haemoglobin