Purpose: Type 2 idiopathic macular telangiectasia (MacTel) is a rare bilateral neurodegenerative disease characterized by alterations in the macular capillary network leading to central vision loss. The purpose of this study was to quantify disease-specific retinal fluorescence lifetime patterns in patients with MacTel using fluorescence lifetime imaging ophthalmoscopy. Participants: Both eyes of 14 patients (mean age ± SEM, 67.8 ± 6.4 years) with a clinical diagnosis of MacTel Type 2 and 14 healthy age-matched controls (age 69.8 ± 6.4 years) were included in this study. Methods: All participants were imaged with a fluorescence lifetime imaging ophthalmoscope (Heidelberg Engineering, Germany). Mean retinal fluorescence lifetimes (Ƭm) were obtained in the short spectral channels (498-560 nm) and long spectral channels (560-720 nm). Clinical features, fundus images, fundus autofluorescence intensity images, spectral domain optical coherence tomography, and corresponding macular pigment optical density measurements using a modified confocal scanning laser ophthalmoscope (mpHRA) were further analyzed. Patients were classified into five phenotypic subgroups using the Gass and Blodi classification. Results: Mean fluorescence lifetimes were significantly prolonged temporal to the fovea in patients with MacTel compared with healthy controls (mean ± SEM: short spectral channels 543 ± 61 ps vs. 304 ± 9 ps; P , 0.0001; long spectral channels: 447 ± 26 ps vs. 348 ± 11 ps; P , 0.0001), and appeared as a crescent or ring-shaped pattern. Prolonged lifetime patterns correlated with decreased macular pigment density on macular pigment optical density measurements. Follow-up examinations were performed in four MacTel patients, which revealed an increase of short spectral channel Ƭ m of 22% over 2.1 years in the temporal fovea. Conclusion: This study confirms that fundus autofluorescence lifetimes display characteristic patterns in patients with MacTel Type 2 disease and provide information about macular pigment and possibly photoreceptor loss. Fluorescence lifetime prolongation correlates with disease severity and may therefore be a useful addition to other imaging modalities for assessing disease progression in MacTel Type 2.
PURPOSE. To investigate fundus autofluorescence lifetime features in patients with hydroxychloroquine (HCQ) retinopathy, and to identify early markers of retinal alterations in patients due to HCQ. METHODS. Patients attending screening for HCQ retinopathy were imaged with a fluorescence lifetime imaging ophthalmoscope. Mean retinal fluorescence lifetimes (Tm) were obtained in a short spectral channel (SSC, 498-560 nm) and a long spectral channel (LSC, 560-720 nm). Screening modalities included fundus images, fundus autofluorescence intensity images (FAF), spectral-domain optical coherence tomography (SD-OCT), visual fields, and multifocal electroretinogram (mfERG). RESULTS. Forty-two eyes of 21 patients on HCQ therapy and 40 eyes of 20 healthy age-matched controls were included. Fourteen eyes of 7 patients with HCQ retinopathy (mean age, 66.1 [SD, 7.7] years) and 28 eyes of 14 patients (mean age, 46.1 [SD, 7.9] years) receiving HCQ without retinopathy were identified. Patients with HCQ retinopathy showed a parafoveal ringshaped or oval area of prolonged mean fluorescence lifetimes. In these areas, mean (6SEM) lifetimes were 374 6 7 ps in the SSC, and on average 19.4% longer compared to the control group (P ¼ 0.0001). Patients on HCQ without retinopathy had retinal fluorescence lifetimes that were similar to the control group. CONCLUSIONS. This study shows that HCQ retinopathy displays characteristic mean fluorescence lifetimes.
Purpose: Stargardt disease is the most common inherited juvenile macular dystrophy and is characterized by yellowish flecks across the posterior pole. The purpose of this study was to investigate fluorescence lifetime changes of retinal flecks over time using fluorescence lifetime imaging ophthalmoscopy. Methods: Longitudinal fluorescence lifetime data of 12 patients with Stargardt disease (mean age ± SEM, 42.25 ± 2.1 years; range, 28-58 years) were acquired using a fluorescence lifetime imaging ophthalmoscope based on a Heidelberg Engineering Spectralis system. Retinal autofluorescence was excited with a 470-nm laser. The emitted fluorescence was detected in two wavelength channels: a short spectral channel (498-560 nm) and a long spectral channel (560-720 nm). The mean retinal autofluorescence lifetimes were calculated and further analyzed with corresponding color fundus images, autofluorescence intensity images, and spectral domain optical coherence tomography. Patients were classified into three subtypes. Results: All patients with Stargardt disease displayed characteristic autofluorescence lifetime patterns. Mean fluorescence lifetime values within areas of yellow flecks were significantly prolonged (long spectral channel 484 ps) compared with the surrounding tissue (long spectral channel 297 ps). In 91.6% of the eyes, flecks with short fluorescence lifetimes (long spectral channel 255 ps) were identified. Short lifetime flecks progressed to flecks with characteristic long lifetimes in 75.1% of eyes within a mean interval of 29.2 months (range 3-45 months). Between baseline and follow-up, the rate of newly developed short lifetime flecks (number/per year) based on subtypes was 2.62 in Group 1, 1.43 in Group 2, and 0.81 in Group 3. Conclusion: Recent onset flecks in Stargardt disease display short fluorescence lifetimes and convert into longer fluorescence lifetime flecks over time. This transition may represent a change in the composition of retinal deposits with accumulation of lipofuscin and retinoid by-products from the visual cycle. With emerging treatment options, these findings may prove useful to monitor disease progression and therapeutic effects.
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