Abstract
Purpose: :
To compare the diameter response of macular and peripheral arterioles in diabetic patients with diabetic maculopathy (D-MAC) or proliferative diabetic retinopathy (PDR) after an increase in the arterial blood pressure induced by isometric exercise.
Methods: :
Twenty-four diabetic patients (mean age 49.8 years, range 31-75 years) were examined of which seventeen had D-MAC and seven had PDR. Using a Retinal Vessel Analyzer (RVA) the diameter response of a macular and a peripheral arteriole located within four disk diameters of the optic disk was recorded in each person before and after increasing the blood pressure by lifting a 2 kg hand weight.
Results: :
There was no significant difference between the baseline diameter of the studied macular(97.3UM ±2.4UM) and peripheral (93.7UM ±3.0UM) arterioles (p=0.34). Lifting the hand weight increased the arterial blood pressure by 27.1±3.8 mmHg (D-MAC) and 18.7±6.1 mmHg (PDR). The increased blood pressure induced no significant change in the diameter of macular arterioles in neither D-MAC patients (-0.09%±0.76%, p=0.97), nor in PDR patients (-0.96%±2.4%, p=0.72). However, the diameter of the peripheral arterioles decreased significantly in D-MAC patients (-1.96%±0.68%, p=0.01) and increased non-significantly in PDR patients (+4.00%±2.33%) (p=0.20).
Conclusions: :
Autoregulation in arterioles supplying the retinal periphery differs among diabetic patients with maculopathy and patients with proliferative retinopathy. The findings may help explain the different responses in the macular area and the retinal periphery in the two retinopathy complications.
Keywords: retina • diabetic retinopathy • blood supply