Diabetic retinopathy: different risk factors for exudates and haemorrhages.

The retinae of 137 patients were examined ophthalmologically and for visual acuity at diagnosis of non-insulin dependent diabetes and again in 1982 and 1983, approximately 7 and 8 years later, when colour photographs were also taken. In 1983, 46% were without detectable retinopathy, 32% had haemorrhages (including microaneurysms) only, 4% exudates alone and 18% both lesions. Those with haemorrhages were more hyperglycaemic than those without retinopathy and those with exudates only. Indeed, those with exudates alone had lower mean glucose levels than those without retinopathy (p less than 0.05). Patients with exudates (+/- haemorrhages) had a lower percentage of the fatty acids of plasma cholesterol esters as linoleate than those without (p less than 0.05) but this did not hold for those developing haemorrhages. Different risk factors appear to operate in different features of diabetic retinopathy. In some respects exudate formation may be more akin to macro than to micro angiopathy.