Published in:
01-07-2011 | Article
Retinal function in relation to improved glycaemic control in type 1 diabetes
Authors:
S. K. Holfort, K. Nørgaard, G. R. Jackson, E. Hommel, S. Madsbad, I. C. Munch, K. Klemp, B. Sander, M. Larsen
Published in:
Diabetologia
|
Issue 7/2011
Login to get access
Abstract
Aims/hypothesis
To study long-term changes in retinal function in response to sustained glycaemia reduction in participants with type 1 diabetes.
Methods
Prospective study using objective measures of retinal function in 17 participants with type 1 diabetes mellitus and minimal to moderate retinopathy who switched from conventional subcutaneous injection to continuous subcutaneous infusion of insulin (CSII).
Results
Glycated haemoglobin HbA1c gradually decreased from 9.1% at baseline before CSII to 7.4% after 1 year on CSII. Glycaemia was markedly reduced within 1 week after initiation of CSII and remained stable thereafter. Dark adaptation and retinal electroretinographic function at 1, 4 and 16 weeks after initiation of CSII were comparable with baseline values, whereas a significant improvement in rod photoreceptor dark adaptation and dark-adapted b-wave amplitudes were seen after 52 weeks (time to rod–cone break −25% [p < 0.0001], time to a standardised rod intercept −13% [p < 0.0001], dark-adapted rod b-wave full-field amplitude +15% [p = 0.0125], standard combined rod–cone b-wave amplitude +8% [p = 0.049]). No detectable change was observed in cone adaptation, electroretinographic cone function or retinopathy.
Conclusions/interpretation
After initiation of CSII, the retinal visual pathway of the rods improved with a delay of more than 4 months, over a time scale comparable with the duration of the diabetic retinopathy early worsening response to sustained glycaemia reduction. This indicates that glycaemia has a long-term effect on the disposition of functional capacity in the retinal visual pathway of rod photoreceptors, the cells that appear to be driving the development of diabetic retinopathy.