Alterations in Retinal Microvascular Geometry in Young Type 1 Diabetes

  1. Tien Y Wong, MD, PhD (twong{at}unimelb.edu.au)1,7
  1. 1. Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Australia
  2. 2. Department of Ophthalmology, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia
  3. 3. Centre for Vision Research, University of Sydney, Sydney, Australia
  4. 4. The Children's Hospital at Westmead, University of Sydney, Sydney, Australia
  5. 5. Department of Medicine, University of Melbourne, Melbourne, Australia
  6. 6. Department of Computer Science, National University of Singapore, Singapore
  7. 7. Singapore Eye Research Institute, National University of Singapore, Singapore

Abstract

Objective: To describe retinal microvascular geometric parameters in young patients with type 1 diabetes.

Research Design and Methods: Patients with type 1 diabetes (aged 12-20 years) had clinical assessment and retinal photography following standardized protocol at a tertiary care hospital in Sydney. Retinal microvascular geometry, including arteriolar and venular tortuosity, branching angles, optimality deviation, and length to diameter ratio (LDR), were measured from digitized photographs. Associations of these geometric characteristics with diabetes duration, HbA1c level, systolic blood pressure (SBP), and other risk factors were assessed.

Results: Of the 1159 patients enrolled, 944 (81.4%) had gradable photographs and 170 (14.7%) had retinopathy. Older age was associated with decreased arteriolar (p=0.024) and venular (p=0.002) tortuosity, and females had larger arteriolar branching angle than males (p=0.03). After adjusting for age and gender, longer diabetes duration was associated with larger arteriolar branching angle (p=<0.001) and increased arteriolar optimality deviation (p=0.018); higher HbA1c was associated with increased arteriolar tortuosity (>8.5% vs ≤8.5%, p=0.008); higher SBP was associated with decreased arteriolar LDR (p=0.002); and higher total cholesterol levels was associated with increased arteriolar LDR (p=0.044) and decreased venular optimality deviation (p=0.044). These associations remained after controlling for HbA1c, retinal vessel caliber and retinopathy status, and were seen in subjects without retinopathy.

Conclusions: Key diabetes-related factors affect retinal microvascular geometry in young type 1 diabetes, even in those without evidence of retinopathy. These early retinal alterations may be markers of diabetes microvascular complications.

Footnotes

    • Received January 13, 2010.
    • Accepted March 7, 2010.