Purpose: To evaluate choroidal circulatory changes in diabetic patients with and without background diabetic retinopathy (BDR) by measuring the retrobulbar circulation with colour Doppler imaging (CDI).
Methods: CDI was used to measure circulatory parameters of the PCA (posterior ciliary artery), CRA (central retinal artery), OA (ophthalmic artery) and the respective veins in 73 diabetic patients and 22 controls in a sitting posture. Among the diabetic patients, 38 patients were without diabetic retinopathy (NDR) and 35 had BDR. A non-parametric Kruskal-Wallis test with a Dunn correction was used for data analysis.
Results: End-diastolic velocity (EDV) in the PCA was decreased (2.55+/-0.80 cm/s) and resistivity index (RI) in the PCA was increased (0.70+/-0.08) in BDR patients compared with the control patients' EDV (3.23+/-1.08 cm/s, p = 0.01) and RI (0.62+/-0.06, p = 0.0003). RI in the CRA was significantly higher in the BDR group (0.74+/-0.09) than in the control group (0.68+/-0.08, p = 0.006). RI in the OA was significantly higher in the BDR group (0.87+/-0.06) compared both with the NDR group (0.83+/-0.07) and with the control group (0.81+/-0.06; p = 0.007, p = 0.004). NDR patients had a significantly higher RI in the PCA (0.67+/-0.08) than control patients (0.62+/-0.06, p = 0.01, while the CRA RI (0.71+/-0.09) did not show significant differences from the control group (0.69+/-0.08, p = 0.32). Decreased EDV in the CRA was detected in NDR patients (2.16+/-0.76 cm/s) compared with the controls (2.72+/-0.92 cm/s, p = 0.007).
Conclusion: The results from this study suggest that not only the retinal but also the choroidal circulation is affected in NDR and BDR patients.