Fluorescence Lifetime Patterns in Macular Telangiectasia Type 2

Abstract

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.

Comparing Fluorescence Lifetime Imaging Ophthalmoscopy in Atrophic Areas of Retinal Diseases

“…In MacTel, a different pattern can be found. 44 , 57 The FLIO pattern in MacTel appears in the SSC as a temporal area of prolonged FLIO lifetimes, which is typically not exceeding the MacTel area of approximately 5° vertical and 6° horizontal eccentricities. 13 Regarding choroideremia, we were able to confirm findings from a previous study indicating that its appearance in FLIO and autofluorescence intensity imaging are not necessarily concordant.…”

Autofluorescence Lifetimes Measured with Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) Are Affected by Age, but Not by Pigmentation or Gender

“…FLIO has shown promising results as a prototype; it holds the potential to diagnose retinal diseases at early stages and may be on its way to become an important imaging modality in the future. [3][4][5][6][7][8][9][10][11][12]25 To use FLIO in clinical studies, background knowledge regarding specific influences on FLIO is important. A previous study by Dysli et al 16 nicely demonstrated that FLIO has good test-retest reliability, which holds true for miosis and mydriasis.…”

“… 3 , 4 Various studies have shown that different retinal diseases, such as age-related macular degeneration and macular telangiectasia type 2 (MacTel), can be detected with FLIO even before other clinical signs of the disease appear, and well before damage is manifest. 5 – 9 Furthermore, FLIO is able to detect disease progression, which was especially highlighted in various cases of Stargardt disease, in which FLIO detects progression approximately 1 to 2 years before these changes are visible in conventional autofluorescence imaging. 10 , 11 In patients with early retinal toxicity due to drugs, such as hydroxychloroquine (Plaquenil), FLIO may also be helpful.…”

Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) in Patients with Choroideremia

“…FLIO shows specific patterns of FLIO lifetimes in AMD, MacTel, hydroxychloro- quine toxicity, Stargardt disease, and other inherited retinal diseases, and it is capable of distinguishing one disease from another. [20][21][22][24][25][26][27]29,37,38,40,41 Changes in FLIO lifetimes can present before any structural, anatomical, or autofluorescence intensity changes appear in conventional imaging techniques. 20,23,24,42 For example, eyes of patients with AMD display a ring-shaped pattern of prolonged FLIO lifetimes in the macular area, which is not seen in FAF intensity images.…”

“…Early FLIO lifeetime changes have been detected in Stargardt disease, patients with macular telangiectasia type 2 (MacTel), and patients who may develop retinal toxicity due to hydroxychloroquine (Plaquenil) supplementation. [20][21][22][23][24] Recently, early retinal changes in family members of patients with MacTel were found with FLIO. 24 Several other diseases, such as age-related macular degeneration (AMD), diabetic retinopathy, and Alzheimer disease, similarly exhibit altered FLIO lifetimes in early disease stages.…”