There is a systematic decrease in choroidal circulatory parameters with an increase in the severity of AMD features associated with risk for the development of CNV, suggesting a role for ischemia in the development of CNV.

The development of CNV and visual loss are associated with lower choroidal circulatory parameters at baseline. In addition, the results suggest that decreases in the foveolar choroidal circulation precede the development of CNV in AMD and may play some role in its development.

Purpose-To investigate the relationship between drusen extent and foveolar choroidal blood flow in non-exudative AMD.Methods-Total drusen area, average druse area, and total drusen number were determined using a computer program developed to quantify the extent of manually outlined drusen from fundus photographs of 157 patients (239 eyes) with non-exudative AMD. Laser Doppler flowmetry was used to assess relative choroidal blood velocity (ChB Vel ), volume (ChB Vol ), and flow (ChB Flow ) in the center of the fovea.Results-We found a significant inverse relationship between total drusen area and ChB Vol or ChB Flow . For every 1 mm 2 increase in total drusen area, ChB Vol decreased by 0.0061 arbitrary units (AU; p=0.03) and ChB Flow decreased by 0.23 AU (p=0.049). Average druse area was also significantly inversely related to ChB Vol and ChB Flow . For every 0.01 mm 2 increase in average druse area, the ChB Vol decreased by 0.0149 AU (p=0.001) and the ChB Flow decreased by 0.4951 AU (p=0.003). Adjustment for age weakened the significance, though it remained strong for average druse area versus ChB Flow (p=0.017) and ChB Vol (p=0.004). The computer-aided quantification of drusen used in this study showed high intra-and inter-grader agreement.Conclusion-In patients with non-exudative AMD, there is an association between increased drusen extent and decreased ChB Vol and ChB Flow . This suggests the presence of ischemia and possibly the reason why patients with high risk drusen are prone to advanced disease.