title: Near-Infrared Autofluorescence Imaging in Geographic Atrophy Using Spectralis Single and Combined Wavelength Modes.
abstract: OBJECTIVE
  The Spectralis Heidelberg retina angiography + optical coherence tomography (OCT) device often fails to acquire near-infrared autofluorescence (NI-AF) due to poor signal because of interference by the beam splitter used for aligning the laser source with the OCT diode light source. We report the rates of successful NI-AF image acquisition using indocyanine green angiography (ICGA) mode (without dye) compared with combined fluorescein angiography (FA) + ICGA mode (without dye) in patients with geographic atrophy (GA).
  
  
  METHODS
  This was a retrospective review.
  
  
  METHODS
  Two hundred images from 50 eyes of 25 patients with GA were included. All patients underwent NI-AF imaging using ICGA (787 nm) and combined FA + ICGA (488 + 787 nm) modes in both eyes. Each eye had macula- and disc-centered imaging. The rates of successful image acquisition were compared using McNemar test.
  
  
  RESULTS
  Successful NI-AF acquisition using ICGA was 48% to 52% in macula-centered views and 36% to 56% in disc-centered views. Only 36% of patients had successful bilateral NI-AF imaging. This improved to 100% in all views in both eyes after switching to combined FA + ICGA mode (P < 0.001). Logistic regression showed no patient or ocular factors were predictive of NI-AF acquisition failure in ICGA mode.
  
  
  CONCLUSIONS
  Acquisition of NI-AF images in GA using ICGA mode has a high failure rate, which can be eliminated by using combined FA + ICGA mode. This finding has implications on the design of imaging protocols for routine assessment and clinical trials of geographic atrophy.
authors.affiliation: From the *UWA Centre for Ophthalmology and Visual Science; †Lions Eye Institute; and ‡Royal Perth Hospital, Perth, Western Australia.
authors.forename: Fred Kuanfu
authors.initials: FK
authors.lastname: Chen
authors.forename: Ying Jo
authors.initials: YJ
authors.lastname: Khoo
authors.forename: Ivy
authors.initials: I
authors.lastname: Tang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D057092:Geographic Atrophy / Q000175:diagnosis*; D006801:Humans; D007208:Indocyanine Green / Q000008:administration & dosage; D007259:Infrared Rays; D016015:Logistic Models; D008297:Male; D061848:Optical Imaging / Q000379:methods*; D012189:Retrospective Studies
chemical_list: D007208:Indocyanine Green