Drusen Area versus Retinal Pigment Epithelium-Drusen Complex Volume in Intermediate Age-related Macular Degeneration

Abstract

 

Purpose:

 

To evaluate the relationship between RPE-drusen complex (RPEDC) volumes from spectral domain optical coherence tomograms and measurement of drusen area from color fundus photographs (CFP), in the baseline eyes of the prospective randomized Age-related Eye Disease Study 2 Ancillary Spectral Domain Optical Coherence Tomography Study (A2A SDOCT Study, clintrials.gov NCT00734487).

 

Methods:

 

Three-dimensional SDOCT images were automatically segmented using validated DOCTRAP software on 314 eyes with intermediate age-related macular degeneration (AMD) and 122 control eyes from the prospective A2A SDOCT study. Certified SDOCT analysts reviewed segmentation for accuracy and corrected gross errors. Total RPE-drusen complex volume (RPEDC) volume was computed within 1-mm and 5-mm rings centered on the fovea. CFP were graded by the Wisconsin Reading Center, scoring for drusen area within the Center Subfield (1-mm dia.) and within the Grid (6-mm dia.).

 

Results:

 

Quantitative assessment was performed on 256 of 314 AMD eyes and 118 of 122 control eyes. Mean (SD) total RPEDC volume was 0.686 (0.213) mm3 in AMD eyes, and 0.550 (0.07) mm3 in control eyes (P<0.001, unpaired t-test). Review of paired CFP images and SDOCT RPEDC volume maps showed regional variations in thickness, such as from geographic atrophy that explained some of the variance in RPEDC volume. Median total RPEDC volumes for both 1- and 5-mm diameter (Fig. 1) were significantly different when binned by CFP score (P=0.0001, Kruskal-Wallis). RPEDC volume and CFP drusen area score were correlated (Spearman’s Rho = 0.54 and 0.50, respectively, P<0.0001).

 

Conclusions:

 

The RPE-drusen complex volume derived from SDOCT images may be a clinically useful tool for distinguishing and assessing AMD. While comparable to drusen area on CFP, this unique measure may enable further risk stratification. Longitudinal study will assess the predictive value of SDOCT-based RPEDC volume in AMD progression.  

 

Clinical Trial:

 

http://www.clinicaltrials.gov NCT00734487

 

Keywords: age-related macular degeneration • imaging/image analysis: clinical