title: Calculation of central retinal artery diameters from non-invasive ocular haemodynamic measurements in type 1 diabetes patients.
abstract: OBJECTIVE
  The aim of the study was to compare the diameter of the central retinal artery (CRA) between patients with diabetes mellitus and healthy subjects in vivo. CRA diameters were calculated from retinal haemodynamic parameters measured with noninvasive measurement techniques.
  
  
  METHODS
  Sixteen patients with type 1 diabetes with no or mild diabetic retinopathy and 16 age-matched healthy controls were included in this study. Total retinal blood flow was assessed by combining bidirectional laser Doppler velocimetry in all veins entering the optic disc with measurements of retinal vessel diameters using a Dynamic Vessel Analyser. Blood flow velocity in the CRA was measured with colour Doppler imaging (CDI). The diameter of the CRA in the optic nerve was then calculated for each subject using the individual ocular haemodynamic data.
  
  
  RESULTS
  Calculated CRA diameters were significantly larger in patients with diabetes (180 ± 13 μm) compared with healthy controls (166 ± 10 μm, p = 0.001). No significant differences were found in retinal blood flow, retinal artery or vein diameters or mean flow velocity of the CRA.
  
  
  CONCLUSIONS
  The data of the present study show increased calculated CRA diameter in patients with type 1 diabetes with no or mild retinopathy. Blood flow velocity measurements in retrobulbar vessels using CDI need to be interpreted with caution in terms of retinal blood flow, because no information about vessel diameters is obtained by this technique.
authors: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors: Berthold
authors: B
authors: Pemp
authors: Alina-Popa
authors: AP
authors: Cherecheanu
authors: Gerhard
authors: G
authors: Garhofer
authors: Leopold
authors: L
authors: Schmetterer
mesh_terms: D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000379:methods*; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology*; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012720:Severity of Illness Index; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D055815:Young Adult
keywords: colour Doppler imaging; diabetes mellitus; retinal blood flow; retinal vessel diameter