The effects of diabetes on retinal function before the onset of clinically detectable retinopathy have been investigated with several methods. Our aim is to evaluate the usefulness of computerized perimetry in early diagnosis of retinal sensitivity impairment in lack of fluorescein angiographic signs of diabetic retinopathy. Seventy diabetic children and adolescents, 39 normoalbuminuric and 31 microalbuminuric patients, and 70 normal subjects were investigated with static computerized perimetry. Normoalbuminuric patients showed functional parameters similar to those of controls, while microalbuminuric patients had a significant reduction of mid-peripheral light sensitivity in comparison with both normoalbuminuric children and controls. Our data suggest that an impaired light sensitivity, in mid-periphery of the visual field, is present in diabetic patients with persistent microalbuminuria.