Ocular haemodynamics and colour contrast sensitivity in patients with type1 diabetes

Background-There is evidence that altered ocular blood flow is involved in the development and progression of diabetic retinopathy. However, the natur e of these perfusion abnormalities is still a matter of controversy. Ocular haemodynamics were characterised with two recently introduced methods. Methods-The cross sectional study was performed in 59 patients with type 1 diabetes with a diabetes duration between 12 and 17 years and an age less t han 32 years and a group of 25 age matched healthy controls. Scanning laser Doppler flowmetry and laser interferometric measurement of fundus pulsatio n amplitude were used to assess retinal and pulsatile choroidal blood flow, respectively. In addition, colour contrast sensitivity along the tritan ax is was determined. Results-Fundus pulsation amplitude, but not retinal blood flow, increased w ith the progression of diabetic retinopathy. Retinal blood flow was influen ced by plasma glucose levels (r = 0.32), whereas fundus pulsation amplitude was associated with HbA(1c) (r = 0.30). In addition, a negative correlatio n between the colour contrast sensitivity along the tritan axis and retinal blood flow was observed. Conclusions-The present study indicates that pulsatile choroidal blood flow increases with the progression of diabetic retinopathy. Increased retinal blood flow appears to be related to loss of colour sensitivity in patents w ith type 1 diabetes.