title: Retinal Vascular Fractals Correlate With Early Neurodegeneration in Patients With Type 2 Diabetes Mellitus.
abstract: OBJECTIVE
  To investigate the correlation between the retinal vascular fractal dimension (Fd) and neurodegenerative changes in patients with no or mild diabetic retinopathy (DR).
  
  
  METHODS
  In this cross-sectional study we examined 103 patients with type 2 diabetes mellitus (T2DM) with no or mild DR. In a randomly selected eye of each patient, Fd was calculated using SIVA-Fractal, a specialized semiautomatic software. Retinal neurodegeneration was evaluated by Topcon 3D OCT-2000 spectral-domain optical coherence tomography (OCT) and by a RETI-scan multifocal ERG (mf-ERG) system in rings one to six. Level of DR was determined by a single trained grader in seven-field fundus photos according to the Early Treatment Diabetic Retinopathy Study (ETDRS) scale.
  
  
  RESULTS
  Mean age and duration of T2DM were 62.3 and 11.6 years, respectively; 46.6% were men. Mean Fd was 1.413 (range, 1.278-1.509) and ETDRS levels were 10 (42.7%), 20 (35.0%), and 35 (22.3%), respectively. Fd correlated inversely with mf-ERG implicit time of ring one (r = -0.25, P = 0.01) and present diabetic neuropathy (P = 0.02), and positively with OCT ganglion cell layer (GCL) thickness (r = 0.20, P = 0.04). In a multivariable linear regression model, Fd was associated with mf-ERG implicit time of ring one (coefficient -0.0021/ms, P = 0.040) and the presence of diabetic neuropathy (coefficient -0.0209 for neuropathy present versus absent, P = 0.041).
  
  
  CONCLUSIONS
  In patients with T2DM and no or minimal DR, independent correlations were found between early vascular and neurogenic changes. Thus, retinal vascular fractal analysis might be considered as a tool to identify patients with early neurodegenerative retinal changes.
authors.affiliation: Department of Ophthalmology, Odense University Hospital, Odense, Denmark 2Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Frydkjaer-Olsen
authors.affiliation: Department of Ophthalmology, Odense University Hospital, Odense, Denmark 2Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Soegaard Hansen
authors.affiliation: Department of Ophthalmology, Odense University Hospital, Odense, Denmark 2Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Knud
authors.initials: K
authors.lastname: Pedersen
authors.affiliation: Institute of Clinical Research, University of Southern Denmark, Odense, Denmark 3The NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.
authors.forename: Tunde
authors.initials: T
authors.lastname: Peto
authors.affiliation: Department of Ophthalmology, Odense University Hospital, Odense, Denmark 2Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Grauslund
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000150:complications* / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012162:Retinal Degeneration / Q000175:diagnosis* / Q000209:etiology; D012171:Retinal Vessels / Q000473:pathology*; D012189:Retrospective Studies; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*