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Luísa Salles de Moura Mendonca, Jeffrey S Heier, David S Boyer, David M Brown, Sumit P Shah, A. Yasin Alibhai, Namrata Saroj, Sabin Dang, Nadia K Waheed; Analysis of choriocapillaris flow impairment in intermediate age-related macular degeneration as a predictor of progression to exudative choroidal neovascularization. Invest. Ophthalmol. Vis. Sci. 2020;61(7):4092.
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Histology and imaging studies demonstrate choriocapillaris (CC) alterations at different stages of age-related macular degeneration (AMD). However, the relationship between CC changes and development of choroidal neovascularization (CNV) has not yet been elucidated. This study aims to evaluate whether the CC flow deficit percent (FD%) measured by spectral-domain OCT angiography (SD-OCTA) correlates with progression to exudative AMD.
Post-hoc analysis of the PRO-CON study, a prospective randomized clinical trial that studied the effect of prophylactic intravitreal aflibercept on the progression of eyes with intermediate AMD to exudative AMD was performed. Subjects that completed 24-months of follow-up and had good quality SD-OCTA images at baseline were included. CC projections were generated using a 20-μm thick slab starting at Bruch's membrane on 6mm × 6mm images. FD% was calculated after binarization using a locally applied Phansalkar threshold. Areas under drusen and retinal projection artifacts were excluded from the final calculation of FD% (Figure 1). Association between FDs% and progression was assessed using logistic regression.
99 eyes from 99 subjects were included for this analysis. The mean age of the subjects was 78.49 ± 7.65; 52.53% were males and 49.49% were in the treatment group. Twelve (12.12%) eyes progressed to exudative CNV. Mean FD% was 46.54 ± 3.72%. FD% showed a significant positive correlation with age (coefficient of 2.54 for 70-80 years; 3.28 for 80-90 years and 5.45 for > 90 years; p = 0.022; 0.005; 0.001; respectively). There was no significant association between FD% and progression (OR = 0.95; p = 0.56; 95% CI 0.79 1.13), after adjusting for age, gender and treatment.
There was no association between FD% and progression to exudative CNV in our small cohort of patients. Association between age and FD%, previously described in the literature, was confirmed by our analysis.
This is a 2020 ARVO Annual Meeting abstract.
A. En face OCTA CC slab and corresponding B-scan. B. RPE structural slab showing drusen and projection artifact. C. en face OCTA CC slab. D. RPE structural slab post binarization with Otsu Global Threshold. E. en face OCTA CC slab post binarization with Phansalkar auto local threshold. F. Resulting en face CC slab used for FD analysis, post drusen and projection artifact removal.
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