title: Drusen detection in retro-mode imaging by a scanning laser ophthalmoscope.
abstract: OBJECTIVE
  The Nidek F-10 is a scanning laser ophthalmoscope that is capable of a novel fundus imaging technique, so-called 'retro-mode' imaging. The standard method of imaging drusen in age-related macular degeneration (AMD) is by fundus photography. The aim of the study was to assess drusen quantification using retro-mode imaging.
  
  
  METHODS
  Stereoscopic fundus photographs and retro-mode images were captured in 31 eyes of 20 patients with varying stages of AMD. Two experienced masked retinal graders independently assessed images for the number and size of drusen, using purpose-designed software. Drusen were further assessed in a subset of eight patients using optical coherence tomography (OCT) imaging.
  
  
  RESULTS
  Drusen observed by fundus photography (mean 33.5) were significantly fewer in number than subretinal deposits seen in retro-mode (mean 81.6; p < 0.001). The predominant deposit diameter was on average 5 μm smaller in retro-mode imaging than in fundus photography (p = 0.004). Agreement between graders for both types of imaging was substantial for number of deposits (weighted κ = 0.69) and moderate for size of deposits (weighted κ = 0.42). Retro-mode deposits corresponded to drusen on OCT imaging in all eight patients.
  
  
  CONCLUSIONS
  The subretinal deposits detected by retro-mode imaging were consistent with the appearance of drusen on OCT imaging; however, a larger longitudinal study would be required to confirm this finding. Retro-mode imaging detected significantly more deposits than conventional colour fundus photography. Retro-mode imaging provides a rapid non-invasive technique, useful in monitoring subtle changes and progression of AMD, which may be useful in monitoring the response of drusen to future therapeutic interventions.
authors.affiliation: Department of Ophthalmology, Columbia University, New York City, New York 10032, USA. ja2660@columbia.edu
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Acton
authors.forename: Robert P
authors.initials: RP
authors.lastname: Cubbidge
authors.forename: Helen
authors.initials: H
authors.lastname: King
authors.forename: Paul
authors.initials: P
authors.lastname: Galsworthy
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Gibson
mesh_terms: D000368:Aged; D004867:Equipment Design; D005260:Female; D006801:Humans; D007834:Lasers; D008268:Macular Degeneration / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D019721:Ophthalmoscopes; D009887:Ophthalmoscopy / Q000379:methods* / Q000592:standards; D010781:Photography; D015203:Reproducibility of Results; D015593:Retinal Drusen / Q000473:pathology*; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence