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Karl Andersen, Alexandra Vitale, Bekah Helene Gensure, Marissa Larochelle, Akbar Shakoor, Albert T Vitale, Paul S Bernstein, Lydia Sauer; Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) in Birdshot Chorioretinopathy: A Possible Tool for Monitoring Disease Activity. Invest. Ophthalmol. Vis. Sci. 2019;60(9):1597.
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© ARVO (1962-2015); The Authors (2016-present)
Effective monitoring of disease activity in birdshot chorioretinopathy (BSCR) has proven difficult. To investigate the characteristics of fluorescence lifetime imaging ophthalmoscopy (FLIO) in patients with BSCR, we performed a cross-sectional study with follow-up imaging and analyzed how fundus autofluorescence (FAF) lifetimes vary with clinical disease activity.
82 eyes of 41 patients (mean age 56 ± 13 years) with HLA-A29 positive BSCR as well as an age-matched healthy control group of 46 eyes of 29 subjects (mean age 57 ± 14 years) were investigated. Patients were imaged initially and then received follow-up imaging one year later. The Heidelberg Engineering Spectralis-based FLIO device was used to investigate a 30° retinal field centered at the fovea. FAF lifetimes were detected in two spectral channels, a short spectral channel (SSC) with a range of 498-560 nm and a long spectral channel (LSC) with a range of 560-720 nm. FAF decays were approximated by a 3-exponential function, resulting in the mean fluorescence lifetime tm.
FAF lifetimes in quiet disease states present similar to healthy eyes (around 400 ps), while eyes with active disease show focally shortened FAF lifetimes (<200 ps) in the LSC. These focal areas show significantly shorter lifetimes compared to the adjacent retina (p<0.01). These changes correspond with abnormalities observed in OCT imaging, especially in the ellipsoid zone. Scars and old lesions, however, show very prolonged lifetimes (>600 ps). Some patients with a clinically quiet exam but progression to an active disease within 3 months of examination also show focally shortened FAF lifetimes at baseline.
Focally shortened FAF lifetimes in the LSC, often located outside of the immediate fovea, are likely associated with disease activity. FLIO may be able to detect disease activity in BSCR, possibly even at very early stages. This application of FLIO may help direct focused OCT imaging to areas of disease activity and may eventually lead to better treatment and follow-up protocols for patients at risk of disease progression.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Fundus autofluorescence (FAF) intensity and lifetime images from the long spectral channel (560 - 720 nm) of a patient with quiet (A) and a patient with active (B) birdshot chorioretinopathy.
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