title: Passive permeability and outward active transport of fluorescein across the blood-retinal barrier in early ARM.
abstract: OBJECTIVE
  To study the passive and active transport of fluorescein across the blood-retina barrier in early age related maculopathy (ARM) (soft drusen > 63 microm, hyperpigmentation and/or hypopigmentation in patients above 50 years of age).
  
  
  METHODS
  15 patients and 10 healthy subjects were included. Morphological changes were graded from 30 degrees fundus photographs using a simplified version of the epidemiological ARM study group classification system. Differential vitreous spectrofluorophotometry was used to assess the transport properties of the blood-retina barrier (that is, passive permeability and unidirectional permeability caused by outward active transport from the vitreous to the blood).
  
  
  RESULTS
  The passive permeability of the patient group was not significantly different from that of the control group. Four patients with passive permeability more than 3 SD above the mean of the control group (mean 1.8 (SD 0.7) nm/s, range 1.0-3.0 nm/s, data normally distributed) all had centrally located drusen > 500 microm and superjacent pigment clumps of 63-500 microm in diameter. There was no significant difference between the unidirectional permeabilities for the patient group and for the control group (mean 47.4 (29.3) nm/s, range 12.7-91.1 nm/s).
  
  
  CONCLUSIONS
  There was no significant difference in the passive permeability and in the unidirectional permeability of fluorescein. However, the study may indicate that the combination of very large drusen and superjacent pigment clumps in ARM may be associated with a deterioration of the blood-retina barrier.
authors.affiliation: Department of Ophthalmology, Herlev Hospital, University of Copenhagen, Denmark. b.moldow@ofir.dk
authors.forename: B
authors.initials: B
authors.lastname: Moldow
authors.forename: M
authors.initials: M
authors.lastname: Larsen
authors.forename: B
authors.initials: B
authors.lastname: Sander
authors.forename: H
authors.initials: H
authors.lastname: Lund-Andersen
mesh_terms: D000368:Aged; D001813:Blood-Retinal Barrier / Q000502:physiology*; D002199:Capillary Permeability / Q000502:physiology; D016022:Case-Control Studies; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D019793:Fluorescein / Q000493:pharmacokinetics*; D005451:Fluorescein Angiography; D006801:Humans; D016014:Linear Models; D008268:Macular Degeneration / Q000175:diagnosis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016011:Normal Distribution; D013050:Spectrometry, Fluorescence; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media; D019793:Fluorescein