Fluorescence Lifetime Imaging in Stargardt Disease: Potential Marker for Disease Progression

Purpose: The purpose of this study was to describe autofluorescence lifetime characteristics in Stargardt disease (STGD) using fluorescence lifetime imaging ophthalmoscopy (FLIO) and to investigate potential prognostic markers for disease activity and progression.

Methods: Fluorescence lifetime data of 16 patients with STGD (mean age, 40 years; range, 22-56 years) and 15 age-matched controls were acquired using a fluorescence lifetime imaging ophthalmoscope based on a Heidelberg Engineering Spectralis system. Autofluorescence was excited with a 473-nm laser, and decay times were measured in a short (498-560 nm) and long (560-720 nm) spectral channel. Clinical features, autofluorescence lifetimes and intensity, and corresponding optical coherence tomography images were analyzed. One-year follow-up examination was performed in eight STGD patients. Acquired data were correlated with in vitro measured decay times of all-trans retinal and N-retinylidene-N-retinylethanolamine.

Results: Patients with STGD displayed characteristic autofluorescence lifetimes within yellow flecks (446 ps) compared with 297 ps in unaffected areas. In 15% of the STGD eyes, some flecks showed very short fluorescence lifetimes (242 ps). Atrophic areas were characterized by long lifetimes (474 ps), with some remaining areas of normal to short lifetimes (322 ps) toward the macular center.

Conclusions: Patients with recent disease onset showed flecks with very short autofluorescence lifetimes, which is possible evidence of accumulation of retinoids deriving from the visual cycle. During the study period, many of these flecks changed to longer lifetimes, possibly due to accumulation of lipofuscin. Therefore, FLIO might serve as a useful tool for monitoring of disease progression. (ClinicalTrials.gov number, NCT01981148.).