title: Corneal autofluorescence in relation to permeability of the blood-aqueous barrier in diabetic patients with clinically significant macular edema and in an age-matched control group.
abstract: OBJECTIVE
  Corneal autofluorescence is related to advanced glycation end products formed by glucose that reaches the cornea via the aqueous humour. The aim of the study was to examine the influence on autofluorescence of changes in permeability of the blood aqueous barrier.
  
  
  METHODS
  Corneal autofluorescence was measured in 50 diabetic patients with clinically significant macular edema and in 28 age-matched control subjects. Permeability of the blood aqueous barrier was assessed using the diffusion coefficient of fluorescein.
  
  
  RESULTS
  Corneal autofluorescence was higher in diabetic subjects than in the control group, mean (SD) at an excitation wavelength of 458 nm was 41.2 ng f-eq/ml (11.7) in diabetic patients and 26.5 ng f-eq/ml (7.3) in the control group, p < 0.001. The mean permeability of the blood aqueous barrier, Kd(F), was 492.0.10(-6) min(-1 )in the diabetic patients and 484.2. 10(-6) min(-1)in the control group. There was no association between permeability of the blood aqueous barrier and corneal autofluorescence, p = 0.99 for the diabetic patients and p = 0.15 for the control group (458 nm).
  
  
  CONCLUSIONS
  Corneal autofluorescence was unaffected by permeability of the blood aqueous barrier suggesting that formation of advanced glycation products is limited by other factors than the concentration of glucose in the aqueous humour, or that other factors unrelated to nonenzymatic glycation of stromal proteins are involved.
authors.affiliation: Department of Ophthalmology, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, DK-2730 Herlev, Denmark. line.kessel@dadlnet.dk
authors.forename: Line
authors.initials: L
authors.lastname: Kessel
authors.forename: Birgitte
authors.initials: B
authors.lastname: Moldow
authors.forename: Jaap A
authors.initials: JA
authors.lastname: van Best
authors.forename: Birgit
authors.initials: B
authors.lastname: Sander
mesh_terms: D000328:Adult; D000368:Aged; D018916:Blood-Aqueous Barrier; D016022:Case-Control Studies; D003315:Cornea / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D004487:Edema / Q000503:physiopathology*; D005453:Fluorescence; D006801:Humans; D008266:Macula Lutea; D008875:Middle Aged; D010539:Permeability; D012164:Retinal Diseases / Q000503:physiopathology*