Abstract
Purpose :
GA, the advanced dry form of AMD, progresses relentlessly but with remarkable interindividual variation. AF is the preferred method to evaluate GA lesion size and growth. qAF further calibrates the AF image intensity to an embedded fluorescence reference, to quantify and compare AF levels between patients and across time (Smith, IOVS, 2011). We sought to divide GA by qAF levels and predominant AMD lesion type into two clinically useful phenotypes.
Methods :
25 Regions-of-interest (ROIs) of 9 eyes of 8 pseudophakic patients with GA secondary to non-neovascular AMD were studied. ROIs included all atrophic lobules in each eye.
We performed near-infrared (NIR), spectral-domain optical coherence tomography (SD-OCT) and qAF imaging. Eyes and ROIs were divided into 2 groups according to the predominant intermediate AMD (iAMD) lesion (soft drusen or subretinal drusenoid deposits (SDD)) on SD-OCT. Mean qAF was then computed for the two groups of ROI.
Results :
Phenotype 1, soft drusen and GA. GA lesions are isolated and “black” on AF, with lower qAF (mean qAF 22.175, SD3.46)
Phenotype 2, SDD and GA. GA lesions are multifocal and “gray” on AF, with higher qAF (mean qAF 54.63, SD 16.74, p=0.0006)
Conclusions :
GA may be conveniently and simply divided by the predominant associated iAMD lesion (soft drusen or SDD) and the qAF levels of the GA lobules into 2 main, non-exclusive phenotypes that may help define two pathways of GA pathogenesis, allow more refined phenotype-genotype correlation, and enable an individualized patient prognosis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.