Author: Sarah Thiele (Germany)
Co-authors: Charlotte Behning, Marlene Saßmannshausen, Matthias Schmid, Frank G. Holz, Steffen Schmitz-Valckenberg, Maximilian Pfau
Purpose
Quantification of the relative ellipsoid zone reflectivity (rEZR) on spectral-domain optical coherence tomography (SD-OCT) is assumed to be an in-vivo surrogate for photoreceptor integrity, potentially representing a candidate biomarker for disease progression in age-related macular degeneration (AMD). The purpose of this study was to compare the rEZR between different AMD disease stages.
Setting/Venue
Cross-sectional analysis of data collected for the observational natural history MACUSTAR study, which aims in developing and validating new methods to study disease progression in intermediate AMD
Methods
SD-OCT volume scans (241 B-scans, field size 30°x25°) of participants with early, intermediate, and late-stage AMD as well as age-similar controls were assessed at baseline. Using an automatic rEZR determination approach, the average rEZR [arbitrary units, AU] of each volume scan, after exclusion of drusen area, was analysed cross-sectionally. Linear mixed-effects models with the rEZR as response variable, adjusted for age, sex and the eccentricity within the volume raster scan, were applied to evaluate the association between AMD staging and the rEZR.
Results
A total of 301 eyes of 301 participants (mean age: 71.2 ± 7.2 years) classified as early AMD (n=34), intermediate AMD (n=168) and late-stage AMD (n=56) as well as controls (n=56) were analyzed. The mean rEZR differed across disease stages with a mean (± standard deviation, SD) of 42.08 (± 33.41) AT (median [interquartile range]: 33.0 [19.1 – 55.4] AU) in the early AMD group, a mean of 37.57 (± 29.76) AU (median: 29.9 [16.8 – 50.0] AU) in the intermediate AMD group and a mean of 19.1 (± 19.39) AU (median: 14.2 [5.9 – 26.4] AU) in the late AMD group compared to controls exhibiting a mean rEZR of 47.91 (± 35.89) AU (median: 38.3 [23.1 – 60.7] AU). The linear mixed-effects model shows a significant decrease of the rEZR of -8.05 in individuals with intermediate AMD (p=0.0011) and of -22.35 in late-stage AMD (p<0.0001) as well as a significant association of the rEZR with age (coefficient estimate: -86.93; p<0.0001) and eccentricity (fitted as a B-spline of degree 2, p<0.0001).
Conlusions
The rEZR correlates with AMD severity, being decreased with more advancing disease stages that are characterized by progressing photoreceptor degeneration. The results of this study warrant further longitudinal analyses to characterize the rEZR as an innovative biomarker and its prognostic value for AMD progression.
Financial Disclosure
Heidelberg Engineering, Carl Zeiss Meditec, Optos, CenterVue provides imaging devices and device for probing retinal function in research activities
Comments
-