Abstract
Purpose :
The association between drusen and the choroid in non-neovascular Age-Related Macular Degeneration (AMD) remains unclear. In this cross-sectional study, we sought to evaluate the relationship between drusen burden (reflected by drusen volume), and choroidal thickness and choroidal intensity.
Methods :
In this IRB-approved study, spectral-domain optical coherence tomography (SD-OCT) images were collected from 28 eyes of 18 subjects with non-neovascular/dry AMD. SD-OCT data were obtained using the Cirrus™ HD-OCT (Carl Zeiss Meditec, Dublin, CA) 512 × 128 macular cube protocol. The Cirrus™ advanced RPE analysis tool was used to automatically compute drusen volumes, and segmented B-scans were reviewed for segmentation errors. OCT data was also imported into previously described 3D-OCTOR grading software at the Doheny Image Reading Center, and the inner and outer borders of the choroid were manually segmented. Following segmentation, the software computed the mean choroidal thickness as well as the mean choroidal intensity (i.e. brightness). The correlation between drusen volume and these choroidal parameters was assessed using Pearson’s analysis.
Results :
The mean age of study subjects was 77 ± 5.50 years (range: 68-87) and 12 were female. The mean drusen volume was 0.06 ± 0.05 mm3 (range: 0.01-0.16), and the mean choroidal thickness was 0.34 ± 0.03 µm (range: 0.30-0.40) and the mean choroidal intensity was 0.36 ± 0.08 log units (range: 0.23-0.53). Choroidal intensity was negatively correlated (r = -0.59, p = 0.001) with choroidal thickness, indicating that thinner choroids tended to be brighter. Choroidal intensity, however, was positively correlated with age (r = 0.45, p = 0.01), suggesting that the choroid got brighter with age. Drusen volume did not show a significant correlation with either choroidal intensity (r = -0.20, p = 0.29) or choroidal thickness (r = 0.30, p = 0.14).
Conclusions :
In this study, choroidal intensity was significantly correlated with choroidal thickness and age. A lower choroidal intensity with increased choroidal thickness may simply reflect the loss of signal with depth inherent to SD-OCT, though this possibility could be re-assessed with enhanced depth imaging. Notably, the drusen burden did not appear to be influenced by these choroidal parameters. The study was not powered, however, to look for small effects.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.