Foveolar choroidal circulation and choroidal neovascularization in age-related macular degeneration

PURPOSE. To investigate in a longitudinal study whether foveolar choroidal blood flow changes are associated with the development of choroidal neovascularization (CNV) in AMD. METHODS. Relative foveolar choroidal blood velocity (ChBVel), volume (ChBVol), and flow (ChBFlow) were assessed in 135 patients with AMD, at baseline and then annually with laser Doppler flowmetry. All study eyes had visual acuity of 20/40 or better and no CNV at the time of enrollment. Comparison of foveolar choroidal circulatory measurements at baseline and their change before the development of CNV was made between eyes that had CNV and those that did not. RESULTS. CNV developed in 28 eyes during the study. Baseline average foveolar ChBVol and ChBFlow in these eyes were 24% (P < 0.0001) and 20% (P < 0.0007) lower than that observed in the 165 eyes in which CNV did not develop. In the eyes with CNV, foveolar ChBVol and ChBFlow decreased by 9.6% and 11.5% before the formation of CNV, whereas in the eyes that did not, they increased by 6.7% (P = 0.006) and 2.8% (P = 0.004), respectively. Eyes with lower baseline foveolar ChBFlow were more likely (risk ratio = 3.47, 95% CI: 1.24-8.70) to show visual loss of three or more lines than were eyes with a higher baseline ChBFlow (P = 0.005). CONCLUSIONS. 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.