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Comparison of short-wavelength blue-light autofluorescence and conventional blue-light autofluorescence in geographic atrophy
  1. Enrico Borrelli1,2,3,
  2. Muneeswar Gupta Nittala1,2,
  3. Nizar Saleh Abdelfattah1,2,
  4. Jianqin Lei1,2,4,
  5. Amir H Hariri1,2,
  6. Yue Shi1,2,
  7. Wenying Fan1,2,
  8. Mariano Cozzi5,
  9. Valentina Sarao6,7,
  10. Paolo Lanzetta6,7,
  11. Giovanni Staurenghi5,
  12. SriniVas R Sadda1,2
  1. 1 Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California, USA
  2. 2 Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
  3. 3 Department of Medicine and Science of Ageing, Ophthalmology Clinic, University G. D'Annunzio Chieti-Pescara, Chieti, Italy
  4. 4 First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
  5. 5 Department of Medicine and Ophthalmology, University of Udine Piazzale S. Maria della Misericordia, Udine, Italy
  6. 6 Istituto Europeo di Microchirurgia Oculare—IEMO, Udine, Italy
  7. 7 Eye Clinic, Department of Biomedical and Clinical Science ‘Luigi Sacco’, Luigi Sacco Hospital, University of Milan, Milan, Italy
  1. Correspondence to Dr SriniVas R Sadda, Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California 90033, USA; ssadda{at}


Background/aims To systematically compare the intermodality and inter-reader agreement for two blue-light confocal fundus autofluorescence (FAF) systems.

Methods Thirty eyes (21 patients) with a diagnosis of geographic atrophy (GA) were enrolled. Eyes were imaged using two confocal blue-light FAF devices: (1) Spectralis device with a 488 nm excitation wavelength (488-FAF); (2) EIDON device with 450 nm excitation wavelength and the capability for ‘colour’ FAF imaging including both the individual red and green components of the emission spectrum. Furthermore, a third imaging modality (450-RF image) isolating and highlighting the red emission fluorescence component (REFC) was obtained and graded. Each image was graded by two readers to assess inter-reader variability and a single image for each modality was used to assess the intermodality variability.

Results The 95% coefficient of repeatability (1.35 mm2 for the 488-FAF-based grading, 8.13 mm2 for the 450-FAF-based grading and 1.08 mm2 for the 450-RF-based grading), the coefficient of variation (1.11 for 488-FAF, 2.05 for 450-FAF, 0.92 for 450-RF) and the intraclass correlation coefficient (0.994 for 488-FAF, 0.711 for 450-FAF, 0.997 for 450-RF) indicated that 450-FAF-based and 450-RF-based grading have the lowest and highest inter-reader agreements, respectively. The GA area was larger for 488-FAF images (median (IQR) 2.1 mm2 (0.8–6.4 mm2)) than for 450-FAF images (median (IQR) 1.0 mm2 (0.3–4.3 mm2); p<0.0001). There was no significant difference in lesion area measurement between 488-FAF-based and 450-RF-based grading (median (IQR) 2.6 mm2 (0.8–6.8 mm2); p=1.0).

Conclusion The isolation of the REFC from the 450-FAF images allowed for a reproducible quantification of GA. This assessment had good comparability with that obtained with 488-FAF images.

  • Autofluorescence
  • Geographic atrophy
  • Age-related macular degeneration
  • Green fluorophores
  • Optical coherence tomography.

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  • Contributors Study concept and design: EB and SRS. Acquisition, analysis or interpretation of data: all authors. Drafting of the manuscript: EB and SRS. Critical revision of the manuscript for important intellectual content: all authors. Statistical analysis: EB, MGN, SRS. Study supervision: EB and SRS.

  • Funding Financial support—Bayer, CenterVue, Genentech, Novartis, Roche. GS: financial support—Novartis, Alcon, Bayer, Allergan, Boehringer Ingelheim, Genentech, Roche, Zeiss Meditec, Heidelberg Engineering, Optos, CenterVue. SRS: financial support—Allergan, CenterVue, Carl Zeiss Meditec, Genentech, Iconic, Novartis, Optos, Optovue, Regeneron, Thrombogenics. 

  • Competing interests None declared.

  • Patient consent Parental/guardian consent obtained.

  • Ethics approval UCLA IRB.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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