title: Fundus near infrared fluorescence correlates with fundus near infrared reflectance.
abstract: OBJECTIVE
  To analyze the occurrence of near infrared (NIR) fluorescence in relation to NIR reflectance, blue-light-excited autofluorescence, angiograms, and funduscopy.
  
  
  METHODS
  Observational consecutive case series in patients with macular diseases. Imaging was performed with a confocal scanning laser ophthalmoscope for NIR reflectance, blue-light-excited autofluorescence, NIR fluorescence, and fluorescein and indocyanine green (ICG) angiograms. In cases in which NIR fluorescence was observed, five to nine images were averaged. The leakage of the scanning laser ophthalmoscope was analyzed.
  
  
  RESULTS
  In the 291 eyes analyzed, NIR fluorescence was observed in 51 and was graded weak in 27 with wet age-related macular degeneration (AMD, 10 cases), dry AMD with pigment clumping (n=7), chronic central serous choroidopathy (CSC; n=5), choroidal nevi (n=2), subretinal hemorrhages (n=2), and chloroquine maculopathy (n=1). Strong NIR fluorescence was found in 24 eyes, with wet AMD (n=14), subretinal hemorrhages (n=8), and choroidal nevi (n=2). Except for four eyes, we observed a strong correlation of NIR fluorescence and increased NIR reflectance at identical fundus location (92.2%). NIR fluorescence corresponded with increased blue-light-excited autofluorescence in 21 of 31 patients with AMD and in 4 of 5 patients with chronic CSC, but in none of the 4 patients with nevi. Funduscopy showed that structures with NIR fluorescence were pigmented or consisted of degraded blood. Barrier filter leakage of the imaging system was 6.2x10(-6).
  
  
  CONCLUSIONS
  The high correlation of NIR fluorescence and reflectance indicated that part of the observed NIR fluorescence is pseudofluorescence, whereas gray-scale analysis indicated that both NIR autofluorescence and pseudofluorescence contribute to the NIR fluorescence images. Quantification of leakage of the imaging system indicated a significant part of the observed NIR fluorescence is NIR autofluorescence. As NIR fluorescence derives from pigmented lesions, melanin is a possible source if NIR reflectance is also increased. Comparison with blue-light-excited autofluorescence showed differences between AMD and patients with nevi. NIR autofluorescence was also detected in single cases of maculopathy without corresponding NIR reflectance.
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Aachen, Germany. aweinberger@ukaachen.de
authors.forename: Andreas W A
authors.initials: AW
authors.lastname: Weinberger
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lappas
authors.forename: Thomas
authors.initials: T
authors.lastname: Kirschkamp
authors.forename: Babac A E
authors.initials: BA
authors.lastname: Mazinani
authors.forename: Julia K
authors.initials: JK
authors.lastname: Huth
authors.forename: Babak
authors.initials: B
authors.lastname: Mohammadi
authors.forename: Peter
authors.initials: P
authors.lastname: Walter
mesh_terms: D015862:Choroid Diseases / Q000175:diagnosis*; D005451:Fluorescein Angiography; D005453:Fluorescence; D005654:Fundus Oculi; D006801:Humans; D007208:Indocyanine Green; D007259:Infrared Rays; D007834:Lasers; D009887:Ophthalmoscopy; D012164:Retinal Diseases / Q000175:diagnosis*
chemical_list: D007208:Indocyanine Green