Abstract
Purpose :
To investigate fundus autofluorescence (FAF) lifetimes in patients with pigment epithelial detachments (PEDs) due to age-related macular degeneration (AMD).
Methods :
63 eyes with PED due to AMD, as well as an age-matched healthy group, were included in this study. 34 of these eyes showed neovascular AMD (nAMD), and 29 showed non-neovascular AMD. Investigations were conducted at the Moran Eye Center in Salt Lake City using the Heidelberg Engineering Spectralis-based FLIO device. A 30° retinal field centered at the fovea was investigated, fluorescence was excited at 473 nm. FAF decays were detected in short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral channels. The mean fluorescence lifetimes (τm) were calculated and compared between various regions in different forms of PED. Multimodal imaging was reviewed by two ophthalmologists masked to clinical history and FLIO who circumscribed and classified the PEDs as either serous (15 eyes), hemorrhagic (2 eyes), fibrovascular (24 eyes) or drusenoid (27 eyes). All PEDs were larger than 350μm.
Results :
Eyes with nAMD show similar FLIO patterns to eyes with non-neovascular AMD. FAF lifetimes in the LSC are prolonged in a ring-shaped pattern localized within the major arcade vessels approximately 3 mm to 6 mm from the foveal center. While serous PEDs exhibit shortened lifetimes (<300 ps), drusenoid PEDs show prolonged lifetimes (>500 ps). These types of PED differ significantly in their fluorescence lifetimes (p<0.01). Lifetimes in fibrovascular PEDs are variable. Areas corresponding to subretinal fluid, choroidal neovascular membranes (CNVM), and hemorrhage display shortened lifetimes (<200 ps). Ex vivo studies of blood also show short autofluorescence lifetimes.
Conclusions :
The previously described non-neovascular AMD-related FLIO pattern is also present in nAMD. However, the presence of short FAF decays found in serous PED, fibrovascular PED, hemorrhage, subretinal fluid, and CNVM may disrupt this ring of prolonged lifetimes. Thus, FLIO appears to differentiate PEDs, hemorrhage and subretinal fluid in AMD. Additionally, ex vivo studies of human blood show short fluorescence lifetimes, which will help to better interpret FLIO images.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.