Abstract
Purpose:
Early detection and prevention of long-term complications by maintaining good metabolic control is the key goal of paediatric diabetes management. Whilst we have readily available diagnostic techniques for retinopathy (fundus photography) and nephropathy (UAER), there is no equally sensitive measure for diabetic neuropathy. The aim of the present study was to assess the utility of in vivo corneal confocal microscopy (IVCCM) in identifying early nerve damage in children with T1DM.
Methods:
25 children with type 1 diabetes mellitus (average age: 13±1 yrs; average duration of diabetes 8 years) with no evidence of retinopathy or microalbuminuria and 10 aged matched control subjects underwent assessment with IVCCM (HRT III) to quantify corneal nerve fibre density (NFD), branch density (NBD) and length (NFL). Each examination took ~ 6 minutes and no child reported that CCM was uncomfortable.
Results:
There was a significant reduction in NFD (no/mm2) (32.5 ± 1.9 v 41.1±1.8, P=0.007), NBD (no/mm2) (50.6 ± 4.5 v 72.5 ± 6.5, P=0.008) and NFL (mm/mm2) (20.6 ± 0.9 v 29.4 ±1.3, P<0.0001) in children with T1DM versus control subjects. Patients were stratified into better (HbA1c <8%, n=15 ) and poorer (HbA1c >8%, n= 10 ) glycaemic control. Even in patients with better (HbA1c-7.9±0.14) glycaemic control, NFD (34.2 ± 2.4, P=0.07), NBD (51.9 ± 4.4, P=0.04), and NFL (21.3 ± 1.2, P<0.0001) were reduced compared to controls. Those with poorer (HbA1c=10.08±0.04) glycaemic control had a further non-significant reduction in NFD (27.3 ± 1.5, P=0.2), NBD (46.7 ± 13.0, P=0.8), and NFL (18.2 ± 1.4, P=0.3) compared to those with better glycaemic control.
Conclusions:
Corneal confocal microscopy detects early corneal nerve damage in children with Type 1 diabetes, which worsens with poorer glycaemic control. CCM provides a fast, non-invasive and well tolerated technique to detect early nerve damage which precedes retinopathy and microalbuminuria. Longitudinal studies are required to predict those who develop overt neuropathy.
Keywords: 498 diabetes •
479 cornea: clinical science