Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) in Patients with Stargardt and Stargardt-like Macular Dystrophies

Abstract

Purpose : Fluorescence lifetime imaging ophthalmoscopy (FLIO) detects early macular changes that may precede later pathology. This study investigates patients with Stargardt disease (STGD) and STGD-like macular dystrophies over time using FLIO.

Methods : The study was IRB-approved. Patients were recruited from retina clinics (MEH, PSB). 30° field retinal images centered at the fovea were collected with a prototype Heidelberg Engineering FLIO that excites fluorescence at 473 nm and detects FLIO lifetimes in short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral channels. Mean fluorescence lifetimes (t_m) were calculated and analyzed (paired sample t-tests). Optical coherence tomography (OCT) and fundus autofluorescence intensity (FAF) were qualitatively compared. Repeat examinations were performed at one year.

Results : 44 patients (mean age: 40±18 years; range: 8-73 years), 35 with STGD and 9 with STGD-like macular dystrophies, and 22 eyes of 22 age-matched controls were included. STGD and STGD-like macular dystrophies show different FLIO patterns from controls. The entire macula (336±148, LSC) and foveal area (347±141, LSC) showed significantly longer lifetimes in patients with STGD compared with healthy controls (172±50 and 230±54, respectively, p<0.001, LSC), whereas unaffected areas did not show significant differences (p=0.45, LSC). Longer central FLIO lifetimes were associated with worse visual acuity (r=0.32, p<0.05, LSC). Flecks of short FLIO lifetimes (around 200 ps, LSC) typically progress to longer lifetimes (around 600 ps, LSC) over one year, and some patients experienced progressive visual disturbances with the transition. New flecks appear in FLIO images before they are visible clinically or with FAF.

Conclusions : FLIO detects unique patterns in STGD and STGD-like macular dystrophies that predate symptoms and may predict progressive visual disturbance. FLIO imaging may be a helpful method to assess disease progression in STGD and STGD-like macular dystrophies.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1: FLIO lifetime and FAF images from the long spectral channel (LSC) in STGD-like macular dystrophy at baseline and after 1 year. Short lifetime flecks progressed to longer lifetimes over time (arrows). Initially flecks were not visible with FAF, but they appear with transition from short to long lifetimes (black arrows) in association with a new scotoma (white arrow).