Evidence Of Drusen Cores Among Patients With High-Risk Drusen in
Age-Related Macular Degeneration
James M. Coombs, MD
Steve Russell, MD, sponsor
Purpose: 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 visible (color) and
fluorescein angiographic image size.
Methods: CAPT participants,
enrolled with HRD associated with ARMD, underwent color fundus photography and
fluorescein angiography as part of a multi-center prospective photocoagulation
choroidal neovascularization risk-reduction trial. For this 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 images were evaluated for the presence or absence of characteristic
halo pattern of drusen substructure. Permission from the CAPT was preceded this
ancillary study.
Results: One
hundred two eyes from fifty one patients were evaluated for drusen cores. Fifty
one (51) of 102 eyes showed evidence of at least one druse possessing coaxial,
central hyperflourescent cores (CCHC). Forty five (45) eyes did not show CCHC .
Six eyes could not be evaluated properly due to poor contrast of photographic
images. Of the 45 participants for which bilateral difference images were
available, concordance was 91%.
Conclusion: This
is the first study to show that patients with age related macular degeneration
with high risk drusen show clinically detectable drusen sub-structure. Further
studies are underway to determine whether CCHCs are present over the duration
of the study and/or have correlation with the genotype and development of
choroidal neovascular membrane formation.
Support: An unrestricted grant from Research to Prevent Blindness.
