REDUCED CHORIOCAPILLARIS FLOW IN EYES WITH TYPE 3 NEOVASCULARIZATION AND AGE-RELATED MACULAR DEGENERATION

Purpose: To study choriocapillaris (CC) flow in eyes with Type 3 neovascularization (NV) and age-related macular degeneration, using optical coherence tomography angiography analysis. Methods: In this multicenter, retrospective, observational study, we collected data from 21 patients with unilateral Type 3 NV and age-related macular degeneration, based on clinical examination, structural optical coherence tomography, and fluorescein angiography when available. An additional group of 20 nonneovascular age-related macular degeneration eyes with unilateral Type 1 or Type 2 NV due to age-related macular degeneration was included for comparison. En face optical coherence tomography angiography imaging (3 x 3 mm scans) with quantitative microvascular analysis of the CC was performed. Main outcome measures were: 1) the percent nonperfused choriocapillaris area; and 2) the average CC signal void size. Results: We included 21 patients with unilateral Type 3 NV (15 female, 71.5%) and 20 patients with unilateral Type 1 or 2 NV (9 female, 45.0% P = 0.118). Mean +/- SD age was 82.1 +/- 7.4 years in the unilateral Type 3 patients and 78.3 +/- 8.1 in unilateral Type 1/2 NV subjects (P = 0.392). The percent nonperfused choriocapillaris area was 56.3 +/- 8.1% in eyes with Type 3 NV and 51.9 +/- 4.3% in the fellow eyes (P = 0.016). The average signal void size was also increased in those eyes with Type 3 NV (939.9 +/- 680.9 mu m(2)), compared with the fellow eyes (616.3 +/- 304.2 mu m(2), P = 0.039). The number of signal voids was reduced in the Type 3 NV eyes (604.5 +/- 282.9 vs. 747.3 +/- 195.8, P = 0.046). The subfoveal choroidal thickness was 135.9 +/- 54.2 mu m in eyes with Type 3 NV and 167.2 +/- 65.4 mu m in the fellow eyes (P = 0.003). In addition, the fellow eyes of patients with unilateral Type 3 NV displayed more significant CC flow abnormalities versus the fellow eyes with unilateral Type 1/2 NV (percent nonperfused choriocapillaris area = 51.9 +/- 4.3% vs. 46.0 +/- 2.1%, respectively, P < 0.0001; and average signal void size 616.3 +/- 304.2 mu m(2) versus 351.4 +/- 65.5 mu m(2), respectively, P < 0.0001; and number of signal voids 747.3 +/- 195.8 vs. 998.5 +/- 147.3, respectively, P < 0.0001). Conclusion: Eyes with unilateral Type 3 NV illustrated increased CC nonperfusion versus fellow nonneovascular eyes. These results suggest that choroidal ischemia may play an important role in the development of Type 3 NV.