Global Analysis of Macular Choriocapillaris Perfusion in Dry Age-Related Macular Degeneration using Swept-Source Optical Coherence Tomography Angiography

Abstract

Citation: Braun PX, Mehta N, Gendelman I, et al. Global analysis of macular choriocapillaris perfusion in dry agerelated macular degeneration using swept-source optical coherence tomography angiography. Invest Ophthalmol Vis Sci. 2019;60:4985-4990. https://doi.org/10.1167/iovs.19-27861 PURPOSE. Swept-source optical coherence tomography angiography (SS-OCTA) was used to investigate if the clinical stage of dry age-related macular degeneration (AMD) was correlated with global and regional macular choriocapillaris (CC) perfusion. METHODS.In this retrospective, cross-sectional study, 6 3 6-mm SS-OCTA images from eyes with early, intermediate, and advanced dry AMD (56 eyes, 41 patients) were analyzed using algorithms described in the literature to assess regional flow deficit percentage (FD%) and average flow deficit size. Regions were defined by concentric areas centered on the fovea: a 1mm-diameter area, 3-mm-diameter ring, 5-mm-diameter area, 5-mm-diameter ring, and 6 3 6mm whole image. Data were modeled using the generalized estimating equations approach.RESULTS. The relationship between age and CC FD% and average flow deficit size was statistically significant (P 0.05) in all regions of analysis by linear modeling. The relationship between dry AMD stage and FD% was statistically significant by linear modeling in the 5-mm ring, and between dry AMD stage and average flow deficit size in the 3-mm ring, 5-mm area, 5mm ring, and 6 3 6-mm whole image.CONCLUSIONS. Linear modeling suggests a statistically significant relationship between dry AMD stage and CC perfusion, most prominent in the more peripheral regions of the macula.

Using the Pathophysiology of Dry AMD to Guide Binarization of the Choriocapillaris on OCTA: A Model

“…Such topographic influence is supported by modeling showing a strong correlation between age and macular CC flow deficit in eyes with dry AMD. 15 Although this support is weakened by self-referentiality (this modeling relies upon the very binarization parameters whose reasonableness is being argued for here), we still think this argument worth making by a previously advocated principle—namely, the cautious utility of disparate methods converging on similar conclusions. A strong correlation between age and macular CC flow deficit in eyes with dry AMD was also affirmed with binarization parameters—Otsu global and Phansalkar local (3-pixel radius), both discussed below—other than the Phansalkar local (15-pixel radius) method used in the referenced modeling.…”

“…Recently, our group completed a study that suggested that dry age-related macular degeneration (AMD) stage had a statistically significant relationship with macular CC flow deficit metrics (Table 1). 15 The Phansalkar local binarization method, based on the mean and standard deviation of grayscale values within a given radius (15 pixels in this study), was developed for effective binarization in low-contrast settings. 3,5 It was used in this study because of the low-contrast character of the CC, its prevalence in the literature, 8,16,17 its compatibility with the known structure of the CC, 7 and reports of its reasonable approximation of average flow deficit size.…”

Prevention of Image Quality Degradation in Wider Field Optical Coherence Tomography Angiography Images Via Image Averaging

“…Second, residual superficial projection artifacts may still have some effect on deeper layer imaging despite the use of projection removal software, as noted in a previous study. 24 Finally, the accuracy of the image registration between scans may affect the quality of the averaged OCTA images.…”

Microbiota mitochondria disorders as hubs for early age-related macular degeneration

“…Even more, choriocapillaris breakdown already occurs during normal aging and precedes degeneration of the RPE, and loss of endothelial cells of the choriocapillaris is one of the earliest detectable events in AMD [ 129 , 130 ]. Linear modeling found a statistically significant relationship between dry AMD stage and choriocapillaris perfusion, most prominent in the more peripheral regions of the macula [ 131 ]. Average foveal choroidal blood flow in the dry AMD is lower than that of age-matched controls, and the effect is caused mainly by a decrease in volume but not the velocity of blood flow [ 132 ].…”