The influence of diabetic dysregulation on refraction was analysed by a short-term and a long-term approach. a) Out of 15 patients admitted due to high blood sugars and followed over weeks, 11 showed refractive fluctuation of 1-6.5 D, in either direction-often with excess hypermetropia, while 4 appeared refractively stable. In those with refractive change a transient increase of lens thickness was suggested from ultrasound measurements. b) Diabetes control was evaluated retrospectively in 74 adult diabetics, mainly based on repeated 24 h urine glucose determinations over a 6-year period. As a group, those with low myopia did not score worse than those who had stayed emmetropic. Among the myopes, diabetes duration was longer in the subgroup where diabetes preceded myopia onset. - All considered, we found no support for dysregulation per se as an underlying factor behind the 'diabetic myopia' previously reported from our clinic.