Changes in drusen‐associated autofluorescence over time observed by fluorescence lifetime imaging ophthalmoscopy in age‐related macular degeneration

Abstract

Purpose To observe fundus autofluorescence (FAF) lifetimes and peak emission wavelength (PEW) of drusen with respect to the pathology of the overlying RPE in the follow‐up of AMD‐patients. Methods Forty eyes of 38 patients (age: 75.1 ± 7.1 years) with intermediate AMD were included. FAF lifetimes and PEW were recorded by fluorescence lifetime imaging ophthalmoscopy (FLIO). Twenty‐six eyes had a follow‐up investigation between months 12 and 36, and 10 at months 37–72. AMD progression was retrieved from color fundus photography (CFP) and OCT. Drusen were classified with respect to changes in the overlying RPE into groups no, questionable or faint, and apparent hyperpigmentation based on CFP. Results Among the 210 hyperautofluorescent drusen found at baseline, those with hyperpigmentation had longer lifetimes and shorter PEW than those without. Drusen without hyperpigmentation had shorter lifetimes and PEW than neighboring RPE (all p < 0.001) at baseline, but drusen lifetimes increased, and PEW shortened further over follow‐up. Eyes, showing AMD progression, had significantly longer FAF lifetimes at baseline than non‐progressing eyes: 282 ± 102 ps versus 245 ± 98 ps, p < 0.001 and 365 ± 44 ps vs. 336 ± 48 ps, p = 0.025 for short and long wavelength FLIO channel, respectively. Conclusions Depending on hyperpigmentation properties, drusen show lifetimes and PEW different from that of adjacent RPE which change over the natural history of AMD. This difference and change, however, might reflect progressive dysmorphia of the RPE rather than representing fluorescence of drusen material itself. Nevertheless, the observed FAF changes could make FLIO a useful tool for the early detection of AMD progression risk.

Fluorescence Lifetime Imaging of Human Retinal Pigment Epithelium in Pentosan Polysulfate Toxicity Using Adaptive Optics Scanning Light Ophthalmoscopy

“…This finding is consistent with drusen without hyperpigmentation in intermediate AMD seen with clinical FLIO. 49 A significant shortening of FL was also associated with hyperfluorescence material at the RPE atrophic border compared to the prolonged lifetimes of the surrounding RPE (see Fig. 2 , column D, row 7, arrow).…”

Fluorescence Lifetime Imaging Ophthalmoscopy of Mouse Models of Age-related Macular Degeneration

“…It has been shown that drusen itself does not have a significant effect on τ m , 48 and increased intracellular lipofuscin is associated with prolonged τ m , especially in the LSC. 49 Given these points, it is likely that the τ m is not related significantly to lipid deposition under the RPE in ApoE −/− mice, but rather to an increase in cellular metabolism related to the compensatory mechanisms, as also implied by the increased TAC.…”

Multimodal imaging and deep learning in geographic atrophy secondary to age‐related macular degeneration

“…Regarding early AMD, a ring‐shaped prolongation of lifetimes in the long spectral channel (emission of 560–720 nm) has been observed in intermediate AMD, making FLIO a candidate for monitoring early changes in AMD (Sauer et al., 2018). In addition, localized lifetime changes over drusen and pre‐atrophic lesions were reported, with shorter lifetimes for drusen without RPE changes and longer lifetimes for drusen with RPE alterations (Schultz et al., 2022; Schwanengel et al., 2023).…”