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.

Impact of Drusen Volume on Quantitative Fundus Autofluorescence in Early and Intermediate Age-Related Macular Degeneration.

Purpose: Drusen volume (DV) and quantitative autofluorescence (qAF) are potential indicators of progression in age-related macular degeneration (AMD). This prospective and observational study examined the association between DV and qAF of the retinal pigment epithelium. Methods: Eighty-eight eyes of 52 patients with early and intermediate AMD were included. The mean follow-up was 9.2 ± 5.6 months, resulting in 312 examinations. DV was extracted from 6 × 6-mm spectral-domain optical coherence tomography scans. qAF was measured using a rotated Delori pattern. The associations between qAF and DV, age, sex, and lens status were investigated using linear mixed models. Results: Patients' mean age was 75.6 ± 5.0 years (range, 61.0-83.4 years). Sixty-eight eyes (77.3%) were from females. No significant association between DV and qAF was found, neither within the total outer Early Treatment Diabetic Retinopathy Study (ETDRS) grid nor for ETDRS segments six to nine (all P > 0.05). Sex and lens status were not associated with qAF (P = 0.429 and P = 0.213, respectively). A significant association between age and qAF (P = 0.025) was found, indicating a decrease of qAF with age. Conclusions: Quantification of DV and fundus autofluorescence did not reveal any correlation in early and intermediate AMD. qAF decreased with age, whereas DV increased in about half of the patients. This finding is a quantitative corroboration that fundus autofluorescence and the buildup of drusen are not correlated processes in AMD.

Repeatability and reliability of quantitative fundus autofluorescence imaging in patients with early and intermediate age-related macular degeneration.

PURPOSE: Quantification of fundus autofluorescence has only recently become available. We report our findings on the evaluation of the repeatability and reliability of quantitative fundus autofluorescence (qAF) measurements in patients with early and intermediate age-related macular degeneration (AMD), using the first approved and commercially available instrument. METHODS: A total of 43 eyes of 22 patients (aged between 52 and 84 years) diagnosed with early and intermediate AMD were included. All eyes were imaged at day 1, 3 months and 6 months using a modified scanning laser ophthalmoscope, equipped with an internal fluorescent reference. Mean qAF values were calculated for the fovea and for each concentric ring of the Delori pattern. Repeatability and reliability were calculated using Bland-Altman analysis and intraclass correlation (ICC). RESULTS: The mean patient age was 73.5 ± 7.9 years. Sixteen patients (73%) were female. qAF repeatability of the eight segments in the middle ring of the Delori pattern (qAFM 8 ) for between sessions was ±8.2%. Agreement at 3- and 6-month follow-up in eyes without retinal changes was ±8.3% and ±9.8%, respectively. Reliability of qAFM 8 was high for all images acquired [ICC = 0.98 (CI: 0.96-0.99), 0.97 (0.93-0.99) and 0.98 (0.92-0.99)]. Agreement at 3- and 6-month follow-up in eyes with retinal changes was ±18.1% and ±20.2%, respectively. Intraclass correlation (ICC) was slightly lower in eyes with retinal changes at 0.93 (0.84-0.97) and 0.96 (0.91-0.98), respectively. CONCLUSIONS: Quantitative autofluorescence shows excellent repeatability and reliability as well as follow-up agreement in patients with early and intermediate AMD without retinal changes. This is relevant when conducting longitudinal studies using qAF.