Abstract
Purpose :
Alterations in retinal vasculature and thickness in intermediate age-related macular degeneration (iAMD) exhibit unique spatial patterns and have provided new insight into disease pathogenesis. Alterations in choroidal architecture in iAMD have also been reported, but their spatial patterns are still unclear. This study addressed this gap by examining choroidal angioarchitecture in iAMD through spatial analysis of the Choroidal vascularity index (CVI).
Methods :
Eyes of healthy individuals and those with iAMD based on Beckman’s classification (n = 30 per group) were matched by age, ethnicity, and gender. Retrospective OCT (Optical Coherence Tomography) volume scans (61 B-scans covering 30° x 25°; Spectralis SD-OCT; Heidelberg Engineering) were acquired and individual B scans marked according to the Spectralis software. These were then assessed for choroidal luminal area (LA), total choroidal area (TCA) and CVI (LA: TCA) using CVIgrid (www.ocularimaging.net/home). Segment values were combined to generate 8 x 8 equal grids of each parameter correcting for these confounders: Fellow eye disease status, visual acuity presence of reticular pseudo drusen, pigmentary abnormalities and drusen load within 5mm circle(mm2). Mean difference of each parameter was plotted as a topographical map and examined for spatial differences between quadrants.
Results :
Loss in TCA in iAMD vs normal eyes was observed across the macula showing greater loss superiorly (Superior: -8.78 ± 3.56%, Inferior: -3.87 ± 2.28%, p<0.0001). LA exhibited similar pattern of change with greater magnitude of loss superiorly (Superior: -6.86 ± 3.64%, inferior: -4.54 ± 2.67% p<0.001). The CVI map displays mixed spatial changes with increase in iAMD vs normal eyes superiorly (Superior: 1.77 ± 1.55%, Inferior: 1.09 ± 1.19%, p<0.05) and reduction nasally (-1.867 ± 0.96%, temporally:0.98 ± 0.98%, p<0.01).
Conclusions :
Loss of LA and TCA in iAMD displayed a superior bias. CVI variation also showed a superior bias as well as nasal differences. These results suggest a disproportional loss of LA to TCA and need for spatial considerations when assessing choroidal parameters in iAMD.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.