BACKGROUND We attempted to illustrate connections between selected metabolic parameters and the inflammation course in patients after cataract operations. PATIENTS AND METHODS A prospective study comprised 64 patients aged between 35 and 88, 41 of them non-diabetics (group I) and 23 type II diabetics (group II). The following blood parameters (patients with an empty stomach) were selected for the study: cholesterol (chol), triglycerides (tri), HDL and LDL cholesterol, blood sugar (BZ), glycolized hemoglobin (HbA 1c) and C-reactive protein (CRP). To assess the course of the inflammation in the anterior chamber of the eye by objective criteria, tyndallometric measurement was used. The changes in the cornea were measured pachymetrically. The investigations were done the day before the operation and the first to third post-operative days. RESULTS CRP was significantly different only in the males in both groups (p = 0.011). No significant differences were measured between the two groups for the blood parameters chol, tri and HDL- and LDL cholesterol. Tyndallometric measurements showed highly significantly increased anterior chamber reaction in the diabetic group (p = 0.0018). A comparison within the diabetic group did not show any significant differences between patients with or without retinopathy (p = 0.48). Comparison of diabetic patients without retinopathy with non-diabetic patients showed a clearly significant difference (p = 0.014) for this parameter. No significant pachymetric difference was found between the two groups (p = 0.49). CONCLUSIONS The disruption in the blood-aqueous barrier and the clinical inflammatory reaction to the cataract operation are stronger in type II diabetics than in non-diabetic patients, especially in the presence of microangioorganopathy.