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J.M. Coombs, J.C. Folk, R.K. Ivins, S.R. Russell, CAPT Study Group; Detection Of Drusen Substructure Among Patients With Bilateral High–Risk Drusen Associated With Age–Related Macular Degeneration . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2155.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate whether patients with bilateral, high risk drusen (HRD) from age–related macular degeneration (ARMD) demonstrate coaxial, central hyperfluorescent cores (CCHC) based upon the difference of color and fluorescein angiographic image size.
Fifty–two Iowa CAPT participants, who were enrolled with HRD associated with ARMD, underwent color fundus photography and fluorescein angiography as part of a multi–center, prospective, interventional risk–reduction trial. Drusen >125µ in diameter were considered HRD. For this ancillary analysis, the green channel (RGB) color and angiographic images were scanned on a Nikon Super Coolscan 4000 at 4,000 pixels per inch2 for both eyes at the entry and exit (4 year) visit. The scanned images were normalized and registered utilizing Adobe PhotoShop 7.0. A difference image was created by subtracting, pixel–by–pixel, the angiographic value from the green channel value. The resulting difference images were evaluated for the presence or absence of characteristic halo pattern of drusen substructure. Permission from the CAPT Executive Committee preceded this ancillary study.
Twenty two eyes of eleven patients were evaluated for CCHCs. Eight subjects had CCHCs in at least one eye. Four patients (8 eyes) exhibited bilateral evidence of CCHCs associated with a subset of drusen. Four additional patients had one eye that demonstrated CCHCs but in three of these the other eye could not be evaluated due to inadequate image contrast. Three subjects had no detectable CCHCs. Of the participants for which bilateral difference images were available, concordance of CCHCs between the right and left eye was 80%.
Eight of the eleven patients evaluated with bilateral HRD associated with ARMD demonstrate clinically detectable, drusen sub–structure. The heterogeneity of these drusen phenotypes may provide clues to drusen genesis or stage. Further studies are underway to determine whether CCHCs are present over the duration of the CAPT study and have relationship to genotype or treatment status.
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