title: Fundus autofluorescence lifetimes are increased in non-proliferative diabetic retinopathy.
abstract: OBJECTIVE
  To discriminate non-proliferative diabetic retinopathy (NPDR) patients from healthy controls by fluorescence lifetime imaging ophthalmoscopy (FLIO).
  
  
  METHODS
  A prototype FLIO (Heidelberg-Engineering, Heidelberg, Germany) was used to examine the retina of 33 patients and 28 controls. As increased fluorescence of the diabetic lens is known, the lenses of 34 patients and 24 controls were investigated as well. Time-resolved decay was detected in two spectral channels (ch1: 498-560 nm, ch2: 560-720 nm) and approximated by a series of three exponential functions yielding in lifetimes (τ1, τ2, τ3), amplitudes (α1, α2, α3) and their amplitude-weighted means (τm).
  
  
  RESULTS
  Significant differences between patients and controls were found for all fundus lifetime components (τm, τ1-τ3) as for the amplitude α3in both spectral channels. Channel 1 showed the largest differences: the average of mean fluorescence lifetime τmin the macula was 259 ± 137 ps in the patients versus 147 ± 69 ps in the controls. A logistic regression model allowed discrimination between study and control group with a sensitivity of 90.09% and a specificity of 71.4% (area under the curve: 0.865). Significantly shorter τmin the patients group than in the control group was detected in channel 2 in the crystalline lens (1587 ± 326 ps versus 1854 ± 384 ps, p = 0.006).
  
  
  CONCLUSIONS
  Fundus Fluorescence lifetimes are significantly increased in NPDR while lens lifetimes are shorter in the patient group. Lifetime changes might be indicative for the accumulation of advanced glycation end products (AGEs) which enables detection of the disease with high sensitivity and specificity possibly bearing diagnostic merit.
authors: Department of Ophthalmology, University Hospital Jena, Jena, Germany.
authors: Johanna
authors: J
authors: Schmidt
authors: Department of Ophthalmology, University Hospital Jena, Jena, Germany.
authors: Sven
authors: S
authors: Peters
authors: Department of Ophthalmology, University Hospital Jena, Jena, Germany.
authors: Lydia
authors: L
authors: Sauer
authors: Department of Ophthalmology, University Hospital Jena, Jena, Germany.|Center for medical optics and photonics, University of Jena, Jena, Germany.
authors: Dietrich
authors: D
authors: Schweitzer
authors: Institute of Biomedical Engineering and Informatics, Technical University Ilmenau, Ilmenau, Germany.
authors: Matthias
authors: M
authors: Klemm
authors: Department of Ophthalmology, University Hospital Jena, Jena, Germany.
authors: Regine
authors: R
authors: Augsten
authors: Department of Internal Medicine, University Hospital Jena, Jena, Germany.
authors: Nicolle
authors: N
authors: Müller
authors: Department of Ophthalmology, University Hospital Jena, Jena, Germany.|Center for medical optics and photonics, University of Jena, Jena, Germany.
authors: Martin
authors: M
authors: Hammer
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods; D061848:Optical Imaging / Q000379:methods*; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D017127:Glycation End Products, Advanced; C517652:hemoglobin A1c protein, human
keywords: advanced glycation end products; diabetic retinopathy; fluorescence lifetime; functional imaging