May 2005
Volume 46, Issue 13
ARVO Annual Meeting Abstract  |   May 2005
Autofluorescence Colocalization With Drusen in Fellow Eyes of Stage 3 and Stage 4 Age–Related Macular Degeneration
Author Affiliations & Notes
  • J.W. K. Chan
    Ophthalmology, Columbia University, New York, NY
  • R.T. Smith
    Ophthalmology, Columbia University, New York, NY
  • V. Sivagnanavel
    King’s College Hospital, London, United Kingdom
  • N.H. V. Chong
    King’s College Hospital, London, United Kingdom
  • Footnotes
    Commercial Relationships  J.W.K. Chan, None; R.T. Smith, None; V. Sivagnanavel, None; N.H.V. Chong, None.
  • Footnotes
    Support  New York Community Trust
Investigative Ophthalmology & Visual Science May 2005, Vol.46, 4300. doi:
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      J.W. K. Chan, R.T. Smith, V. Sivagnanavel, N.H. V. Chong; Autofluorescence Colocalization With Drusen in Fellow Eyes of Stage 3 and Stage 4 Age–Related Macular Degeneration . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4300.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract: : Purpose: Autofluorescence (AF) images with hyperfluorescence indicate an abnormal accumulation of lipofuscin in the retinal pigment epithelium (RPE). We determined the colocalization of drusen with hyperfluorescence in fellow eyes of stages 3 and 4 age–related macular degeneration (AMD) Methods: We previously developed an accurate and reproducible digital technique of segmenting drusen in fundus images. A similar approach was used to segment hyperfluorescent regions in AF images. The difference was that after leveling the AF image by a geometric model, a 1.5 standard deviation above the local mean was used as a threshold. Nineteen images were selected in two groups: ten patients in the Drusen–Drusen (D–D) group had Stage 3 AMD (bilateral large soft drusen, >125 micron, one eye chosen at random) and nine patients in the Drusen–Geographic Atrophy (D–GA) group had Stage 4 AMD (large soft drusen in both eyes and geographic atrophy in one eye, fellow eye studied). The photographic and SLO images were precisely registered using Matlab for lesion colocalization. The areas of hyperAF and drusen were measured as percentages of the 3000 micron region, and the percentage of total hyperAF that colocalized with drusen was calculated. Results: The D–D group showed significant colocalization of hyperAF with drusen (40.67 ± 13.18 %). The D–GA group exhibited low colocalization (10.49 ± 8.95 %). The p–value for the t–test was 0.00001. Conclusions: We compared drusen in photographs to focal lipofuscin accumulation in AF images of fellow eyes of stage 3 and stage 4 of AMD. Our results show that focally–increased lipofuscin may precede or coexist with early stages of AMD. In the D–GA group, hyperAF was found mostly adjacent to, but not within drusen. At advanced stages, drusen–associated lipofuscin may be dispersed in fellow eyes of the D–GA group, and could be a marker for disease progression in AMD.

Keywords: age-related macular degeneration • imaging/image analysis: clinical • drusen 

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