Longitudinal Association Between Drusen Volume and Retinal Capillary Perfusion in Intermediate Age-Related Macular Degeneration

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.