Longitudinal association between drusen volume and retinal capillary perfusion in intermediate age-related macular degeneration

Abstract

PURPOSE. To evaluate vascular changes in the superficial and deep retinal capillary plexus (SCP, DCP) and their association with drusen volume changes in intermediate age-related macular degeneration (iAMD). METHODS. Patients with iAMD were examined at baseline and 12 months thereafter. Drusen volume was extracted from 20° ☓ 20° OCT scans using a 3-mm ETDRS grid using a customized algorithm with manual correction. Vessel density (VD) and flow area (FA) were extracted from 3 ☓ 3 mm SD-OCT-A scans after manual correction of the segmentation. Associations were investigated using multiple regression models. RESULTS. We used 31 eyes of 31 patients for evaluation. The mean age at baseline was 74.9 ± 5.4 years; 26 patients were female. Baseline visual acuity (VA) was 0.05 ± 0.08 logMAR (Snellen equivalent approximately 20/22). The initial mean 3-mm central drusen volume was 0.144 ± 0.136 mm3. A significant association with the signal strength index was consistently found, therefore all capillary measurements were corrected. VD in the same area was 49.88% ± 7.38% and 55.43% ± 9.31% for the SCP and DCP, respectively. The baseline FA resulted in 3.292 ± 0.218 mm2 and 3.433 ± 0.224 mm2 for the SCP and DCP, respectively. No association was found between changes in drusen volume and FA or VD after 12 months (all P > 0.05). VA worsened (P = 0.013) and the foveal FA of the SCP increased significantly (P = 0.014). CONCLUSIONS. No significant association was found between the increase in drusen volume in iAMD and capillary retinal perfusion over a 12-month follow-up. Although VA decreased statistically over this time period, the foveal FA of the SCP increased.