Diabetic maculopathy

Ophthalmic survey of a diabetic clinic. I: Ocular findings

A medical diabetic clinic was examined for evidence of diabetic eye disease. Of 681 patients invited for ocular examination 96.6% attended for screening. The results for insulin dependent diabetics (IDDs) and non-insulin dependent diabetics (NIDDs) were analysed separately and the major findings were: Cataracts were present in 40.8% of IDDs and 46.2% of NIDDs, with an increased incidence with advancing age. For younger age groups there were significantly more cataracts in IDDs than in NIDDs (p less than 0.001). Cataract extraction was required in 4.2% of the patients, which is higher than the general population. The presence of retinopathy was related to the duration of diabetes (p less than 0.001) but not to age of onset of diabetes. Retinopathy was found in 43.4% of IDDs and 20.1% of NIDDs. Sight threatening retinopathy was present in 13.3% of IDD and 4.3% of NIDD eyes. Advanced diabetic eye disease was seen in 0.6% of eyes.

Reversal of insulin resistance in type I diabetes after treatment with continuous subcutaneous insulin infusion

Insulin responsiveness was studied with the euglycaemic glucose clamp technique in seven patients with type I diabetes and in six control subjects matched for age and weight. The glucose disposal rate was significantly reduced in the diabetic subjects when they were receiving conventional insulin treatment compared with the control group, showing insulin resistance in the diabetics. The diabetic patients were again studied after eight days of intensified metabolic control achieved with continuous subcutaneous insulin infusion. During the infusion a more physiological insulin regimen was used compared with their regular treatment, less of the total insulin dose being given as continuous infusion and more as bolus doses before meals. The insulin resistance in the diabetics was largely reversed after this improved metabolic control. Dose response studies showed an increased glucose disposal rate at all plasma insulin concentrations, including the maximum insulin concentration, indicating a predominant effect of the continuous infusion regimen at the postreceptor level. The improved insulin effect seen with continuous subcutaneous insulin infusion could be due to the improved metabolic control achieved as well as the more physiological regimen.