Point-to-point associations of drusen and hyperreflective foci volumes with retinal sensitivity in non-exudative age-related macular degeneration

ObjectivesTo evaluate the quantitative impact of drusen and hyperreflective foci (HRF) volumes on mesopic retinal sensitivity in non-exudative age-related macular degeneration (AMD).MethodsIn a standardized follow-up scheme of every three months, retinal sensitivity of patients with early or intermediate AMD was assessed by microperimetry using a custom pattern of 45 stimuli (Nidek MP-3, Gamagori, Japan). Eyes were consecutively scanned using Spectralis SD-OCT (20 degrees x 20 degrees, 1024 x 97 x 496). Fundus photographs obtained by the MP-3 allowed to map the stimuli locations onto the corresponding OCT scans. The volume and mean thickness of drusen and HRF within a circle of 240 mu m centred at each stimulus point was determined using automated AI-based image segmentation algorithms.Results8055 individual stimuli from 179 visits from 51 eyes of 35 consecutive patients were matched with the respective OCT images in a point-to-point manner. The patients mean age was 76.85 +/- 6.6 years. Mean retinal sensitivity at baseline was 25.7 dB. 73.47% of all MP-spots covered drusen area and 2.02% of MP-spots covered HRF. A negative association between retinal sensitivity and the volume of underlying drusen (p < 0.001, Estimate -0.991 db/mu m(3)) and HRF volume (p = 0.002, Estimate -5.230 db/mu m(3)) was found. During observation time, no eye showed conversion to advanced AMD.ConclusionA direct correlation between drusen and lower sensitivity of the overlying photoreceptors can be observed. For HRF, a small but significant correlation was shown, which is compromised by their small size. Biomarker quantification using AI-methods allows to determine the impact of sub-clinical features in the progression of AMD.

Automated summary

This study evaluated the quantitative impact of drusen and hyperreflective foci (HRF) volumes on mesopic retinal sensitivity in age-related macular degeneration (AMD) patients. The results showed a negative correlation between the volume of drusen and HRF and retinal sensitivity. The study highlights the use of AI-based methods to assess the impact of cellular changes on the development of AMD.