Blood pressure and the progression of mild background diabetic retinopathy.

A retrospective 5-year study examined the relationship between blood pressure and the severity and progression of mild background retinopathy in 48 patients with non-insulin-dependent diabetes and 38 with insulin-dependent diabetes who did not receive treatment in either eye for at least 3 years from their initial visit. All patients had annual medical and ophthalmic examinations including fundus photography. Retinopathy was assessed from fundus photographs using the Hammersmith grading system. Initial mean systolic and diastolic blood pressures (mm Hg) were significantly higher in those with non-insulin-dependent diabetes (149/88) than in patients with insulin-dependent diabetes (129/81). The former had significantly worse retinopathy than the latter initially and at 5 years. When non-insulin-dependent patients were grouped according to systolic blood pressure, those with readings above 160 mm Hg had significantly more severe retinopathy than those with readings below 140 mm Hg. Blood pressures initially and at 3 years were not significantly different between patients who received photocoagulation (five with insulin-dependent and six with non-insulin-dependent diabetes and those who did not in either group. There was significant correlation between systolic blood pressure and severity of retinopathy in patients with non-insulin-dependent disease, but the change in severity of retinopathy at 5 years did not correlate with blood pressure in either group.