Session Title: Imaging I
Session Date/Time: Thursday 26/09/2013 | 08:30-10:30
Paper Time: 08:54
Venue: Hall 3 (Level 0)
First Author: M.Zinkernagel SWITZERLAND
Co Author(s): C. Dysli M. Abegg M. Menke J. Kowal
Choroideremia is a rare hereditary disease that leads to loss of vision due to progressive degeneration of the choriocapillaris, the retinal pigment epithelium, and the photoreceptors. Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) is a novel imaging method that allows non-invasive measurements of fluorescence lifetimes in vivo in the retina. Fluorescence lifetime characteristics are influenced by various layers of the retina and probably by the underlying choroid and sclera. We wanted to assess the relative contribution of the sclera on fluorescence lifetime characteristics of the retina in vivo.
Subjects were recruited from the specialist clinics for hereditary retinal diseases at the Department of Ophthalmology at the University Hospital of Bern.
Fluorescence lifetime measurements of retinae of healthy controls and patients with choroideremia were obtained using a Fluorescence Lifetime Imaging Ophthalmoscope (FLIO). Fluorescence decay times were measured in a short wavelength channel (498 – 560 nm) and in a long wavelength channel (560 – 720 nm). Short fluorescent lifetimes (tau 1), long fluorescent lifetimes (tau 2) and mean fluorescence lifetimes (tau mean) in each channel were calculated for each acquired pixel within the retina by time-correlated single photon counting. For comparison purposes an ETDRS grid was used to average fluorescent lifetimes for different retinal areas and the anatomical changes were verified by OCT imaging. Fluorescence lifetimes of each ETDRS area in choroideremia were compared with the corresponding area in healthy, age matched controls.
For the short wave length channel (498 – 560 nm) average mean fluorescence lifetimes were significantly longer in retinae affected with choroideremia versus healthy controls (p<0.05). For the long wave length channel (560 – 720 nm) the average mean fluorescence lifetimes in choroideremia patients was significantly longer than in healthy age matched controls (p<0.05).
Fluorescent lifetime imaging in choroideremia may be useful for monitoring of disease progression. Additionally, the distinct fluorescence lifetime characteristics seen in choroideremia may help to gain a better understanding of the factors influencing fluorescence lifetimes of the retina.