Morphologic and functional characterization of macular telangiectasia type 2

• Applicant: Dr. Simone Tzaridis
• Subject Area: Ophthalmology
• Term: from 2018 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 406053827

Macular telangiectasia type 2 (MacTel) is a bilateral retinal disease of unknown cause bearing characteristic vascular alterations and neurodegenerative changes that usually arise in the temporal parafovea. Its prevalence is estimated to be 0.1% in persons 40 years and older and first symptoms usually arise around the age of 57. A typical and early symptom is a reduced reading ability due to paracentral scotomata resulting from neurodegenerative changes. A major complication of MacTel is the development of secondary neovascularizations, which may result into a rapid and irreversible vision loss without appropriate treatment. While secondary neovascularizations may be treated effectively with intravitreal VEGF (vascular endothelial growth factors) -inhibitors, a causative treatment for MacTel is not available so far. For this study, the largest MacTel patient cohort in Germany, including 190 study participants, is available in our study center in Bonn. The purpose of this study is to contribute to the knowledge and understanding of the pathophysiology of MacTel. This is crucial for the development of targeted therapeutic strategies aiming to delay or stop disease progression and for the improvement of patient care. The first goal of this project is to unravel prognostic factors for the development of secondary neovascularizations. Potential clinical and imaging risk factors shall be discovered and the neovascularizations shall be characterized in detail via multimodal imaging (OCT-angiography) in MacTel patients. Moreover, stereoscopic function and the impact of paracentral scotomata on three-dimensional perception in patients with MacTel shall be examined for the first time. This is crucial, since these patients rarely suffer from central vision loss, but very frequently exhibit visual disturbances such as reading difficulties affecting their health-related quality of life. At a third step, the characteristic distribution and loss of density of macular pigment shall be established as a biomarker and predictor of disease progression. Finally, new ultrahigh resolution imaging methods that enable the imaging of single photoreceptors and their distribution patterns (adaptive optics) as well as quasi-histologic imaging of single retinal layers and vascular structures in-vivo (OCT-angiography) shall be used, in order to examine eyes with very early disease stages. The underlying purpose of this project is to characterize earliest pathologic alterations of MacTel, to contribute to the understanding of its pathophysiology and to address a crucial issue in MacTel research: Is MacTel a primarily neurodegenerative or vascular disease?

• DFG Programme: Research Grants