Abstract
Purpose :
Colour and contrast sensitivity are affected early in the course of diabetes mellitus (DM). However, not all studies have reported these deficits in children with DM compared with controls. Previous findings may have been influenced by the characteristics of the vision tests used, e.g. lack of sensitivity, bias towards Blue-Yellow errors or high cognitive demands. The purpose of the study was to evaluate colour and contrast vision, and retinal thickness in children with type 1 DM (T1DM) compared with age matched controls.
Methods :
A prospective case-control study of 9-14 year old children with T1DM (n=24) and age matched controls (n=24) assessed the colour (RG: Red-Green; BY: Blue-Yellow) and contrast (BW: Black-White) thresholds (using a custom-designed iPad game, designed to minimise BY biases and the need for advanced cognitive skills) and retinal thickness (using Optical Coherence Tomography) in the right eye. Non-mydriatic fundus photography was performed to document retinal health. Data on DM related variables from children with T1DM included duration of DM, glycemic control (HbA1c: Glycated hemoglobin) and blood glucose level (BGL) at the time of testing.
Results :
T1DM children had significantly higher colour (RG and BY) but not contrast (BW) thresholds than controls. T1DM children also had significantly greater total (TR) and inner (IR) retinal thickness, but not Retinal Nerve Fibre Layer (RNFL) or Ganglion Cell Complex (GCC) thickness (see Table 1). The median (IQR) DM duration, HbA1c and BGL of T1DM children were 4 (3–8) years, 9% (8–10%) and 12 (9–14) mmol/L, respectively. Significant negative correlations were observed between TR, IR thickness and BGL (Spearman’s rho (ρ): TR= –0.50, IR= –0.44; p<0.05) and, between IR thickness and DM duration (ρ= –0.62, p=0.002). No significant correlations were observed between the visual thresholds, RNFL and GCC thickness or any DM variables. No child with T1DM had visible retinopathy in the fundus photographs.
Conclusions :
Children with T1DM showed higher RG and BY colour discrimination thresholds than controls. Retinal thickness changes were associated with BGL and the duration of DM. These results indicate that abnormalities in colour vision and retinal thickness in children with T1DM may precede the development of visible retinopathy changes.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.