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J.E. Grunwald, T.I. Metelitsina, J.C. DuPont, G.S. Ying; Decreases in the Foveolar Choroidal Circulation Precede the Appearance of Choroidal Neovascularization (CNV) in Age Related Macular Degeneration (AMD) . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2167.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate longitudinally choroidal blood flow in patients with AMD.
We are following a cohort of 125 AMD patients in which relative foveolar choroidal blood velocity (ChBVel), volume (ChBVol) and flow (ChBFlow) are assessed yearly using laser Doppler flowmetry (Oculix instrument). Of these patients, 122 have had a year–1, 90 patients have had a year–2, and 58 patients have had a year–3 measurement. All study eyes had visual acuity of 20/40 or better and no choroidal neovascularization (CNV) at the time of enrollment. Results are shown in arbitrary units (AU).
16 eyes have developed CNV during the study. Average ChBFlow and ChBVol at baseline were significantly lower in the 16 eyes that later developed CNV (6.7 ± 0.6, ± 1 SE and 0.19±0.02, respectively) than in the 156 eyes that did not develop CNV (8.1 ± 0.4 and 0.25±0.01; univariate analysis, p=0.02 and p=0.003, respectively ). In 9 of these 16 eyes that developed CNV we determined blood flows two times prior to the appearance of CNV. During the year preceding the appearance of CNV, 8 of these 9 eyes showed large ChBFlow decreases that ranged between 3% and 47%. Average ChBFlow decrease for these 9 eyes was 19± 19% (paired t–test, p=0.03). To compare the circulatory changes between eyes that did and did not develop CNV we calculated an average annual change for each of the two groups. In the eyes that developed CNV, ChBVol decreased annually by –0.05 AU before the development of CNV, while in eyes that did not develop CNV, ChBVol increased annually by +0.004 AU (univariate analysis, p=0.03). Although we have little data on patients that have lost more than three lines of visual acuity, our results suggest that eyes with lower ChBVel at baseline are three times more likely to develop a 3 lines loss of vision than eyes with higher ChBVel (chi–square, multivariate model, p=0.02).
Our results suggest that in AMD decreases in the foveolar choroidal circulation and possibly ischemia may be associated with and may precede the development of CNV, just as in most of the other types of neovascularization throughout the body.
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