Early Neural and Vascular Changes in the Adolescent Type 1 and Type 2 Diabetic Retina

Abstract

Purpose This cross-sectional study examines the existence and frequency of functional and structural abnormalities in the adolescent type 1 diabetic retina. We also compare the results to those of adolescents with type 2 diabetes. Methods Thirty-two adolescents with type 1 diabetes (5.7 ± 3.6 yrs; mean duration ± SD), 15 with type 2 diabetes (2.1 ± 1.3 yrs) and 26 age-matched control subjects were examined. Multifocal electroretinogram (mfERG) responses from 103 retinal regions were recorded. Optical coherence tomography was used to measure retinal thickness. Vascular diameter around the optic nerve was also assessed. Results Nine of the 32 (28%) adolescents with type 1 diabetes and 6 of the 15 (40%) with type 2 diabetes had significant mfERG implicit time delays compared to 2 of the 26 controls (8%). Retinal thicknesses in both patient groups were significantly (p ≤ 0.01) thinner than controls. The type 2 group also showed significant (p ≤ 0.03) retinal venular dilation (235.8 ± 5.9μm) compared to controls (219.6 ± 4.0μm). Conclusions The present study illustrates that subtle but significant functional and structural changes occur very early in type 1 diabetes. Adolescents with type 2 diabetes appear to be more affected than those with type 1 diabetes. Further longitudinal examination of the etiology and progression of these abnormalities is warranted.

Neuroretinal Dysfunction With Intact Blood-Retinal Barrier and Absent Vasculopathy in Type 1 Diabetes

“…mfERG findings showed generalized decrease amplitudes that are consistent with changes at photoreceptor/bipolar cell circuits. Recent studies (41)(42)(43) reported local neurophysiological changes in type 1 diabetes, as assessed by mfERG. Although these local neurophysiological changes show the expected interindividual variability (in terms of range of amplitude values), ROC and AUC analyses showed that relatively high sensitivity is observed for electrophysiological measures at high specificities, confirming the presence of sensitive early measures of specific neural damage that may potentially be used as biomarkers for detecting neural changes independently of vascular lesions.…”

Associations between Local Retinal Thickness and Function in Early Diabetes

“…This finding is in agreement with other studies done in our laboratory. 15,28 Type 1 and Type 2 diabetes have very different presentations and the two diseases affect vascular and neural health with different time courses and natural histories. The reasons for the retinal function differences we observed between the Type 1 and Type 2 groups, therefore, could be related to differences in the pathophysiologies and comorbidities of the two diseases.…”

Cardiovascular Disease Risk Factors in Youth With Diabetes Mellitus

“…141,142 There are limited data in youth with adolescents with T2DM, but these data suggest similar retinal abnormalities are developing. 143,144 Factors influencing retinopathy in children with T1DM include vitamin D deficiency, 145 BP, 146 duration of disease, 147 and glucose control. 148, 149 The prevalence appears to be declining in both children 150 and adults, 138 possibly related to more intensive treatment.…”